Return buffered input and output streams from ProjectFilesystem
Return buffered input and output streams from ProjectFilesystem

Summary:
There's really no reason to use unbuffered I/O anywhere in
Buck. In particular, the dd-plist library contains this gem, where it
loops in a tight loop reading one byte at a time from an InputStream:

https://code.google.com/p/plist/source/browse/trunk/src/main/java/com/dd/plist/PropertyListParser.java#63

This works around it by always returning buffered input and output
streams from Project Filesystem. If we want, we can add separate
methods to return unbuffered I/O streams.

Test Plan:
Measured perf before and after by generating FBDataModel
project in fbobjc:

https://phabricator.fb.com/P9023396

User-space time in Buck dropped from about 4.8 seconds per run to
about 2.5 seconds per run.

robbertvanginkel/buck,mogers/buck,sdwilsh/buck,davido/buck,davido/buck,dushmis/buck,mogers/buck,marcinkwiatkowski/buck,bocon13/buck,vschs007/buck,rhencke/buck,davido/buck,stuhood/buck,1yvT0s/buck,clonetwin26/buck,illicitonion/buck,grumpyjames/buck,shs96c/buck,dushmis/buck,sdwilsh/buck,shybovycha/buck,Learn-Android-app/buck,LegNeato/buck,OkBuilds/buck,marcinkwiatkowski/buck,shybovycha/buck,Heart2009/buck,JoelMarcey/buck,vschs007/buck,daedric/buck,neonichu/buck,zhan-xiong/buck,dushmis/buck,dpursehouse/buck,k21/buck,artiya4u/buck,OkBuilds/buck,neonichu/buck,LegNeato/buck,brettwooldridge/buck,bocon13/buck,Addepar/buck,daedric/buck,luiseduardohdbackup/buck,raviagarwal7/buck,kageiit/buck,shybovycha/buck,shs96c/buck,vine/buck,hgl888/buck,mikekap/buck,brettwooldridge/buck,rmaz/buck,hgl888/buck,janicduplessis/buck,zhuxiaohao/buck,kageiit/buck,Learn-Android-app/buck,rhencke/buck,stuhood/buck,mikekap/buck,mogers/buck,grumpyjames/buck,justinmuller/buck,Heart2009/buck,MarkRunWu/buck,marcinkwiatkowski/buck,justinmuller/buck,stuhood/buck,raviagarwal7/buck,zpao/buck,tgummerer/buck,darkforestzero/buck,JoelMarcey/buck,k21/buck,Distrotech/buck,saleeh93/buck-cutom,grumpyjames/buck,Addepar/buck,darkforestzero/buck,robbertvanginkel/buck,nguyentruongtho/buck,lukw00/buck,siddhartharay007/buck,sdwilsh/buck,robbertvanginkel/buck,lukw00/buck,brettwooldridge/buck,illicitonion/buck,OkBuilds/buck,JoelMarcey/buck,artiya4u/buck,raviagarwal7/buck,bocon13/buck,OkBuilds/buck,raviagarwal7/buck,shs96c/buck,marcinkwiatkowski/buck,illicitonion/buck,justinmuller/buck,grumpyjames/buck,zpao/buck,Addepar/buck,JoelMarcey/buck,Heart2009/buck,vine/buck,rhencke/buck,raviagarwal7/buck,luiseduardohdbackup/buck,tgummerer/buck,JoelMarcey/buck,zpao/buck,stuhood/buck,vine/buck,saleeh93/buck-cutom,luiseduardohdbackup/buck,darkforestzero/buck,bocon13/buck,rmaz/buck,Dominator008/buck,JoelMarcey/buck,marcinkwiatkowski/buck,Addepar/buck,SeleniumHQ/buck,lukw00/buck,vschs007/buck,romanoid/buck,k21/buck,Learn-Android-app/buck,mogers/buck,Dominator008/buck,sdwilsh/buck,bocon13/buck,romanoid/buck,davido/buck,shs96c/buck,facebook/buck,dsyang/buck,rowillia/buck,dpursehouse/buck,saleeh93/buck-cutom,sdwilsh/buck,ilya-klyuchnikov/buck,Distrotech/buck,nguyentruongtho/buck,SeleniumHQ/buck,rowillia/buck,facebook/buck,mikekap/buck,davido/buck,1yvT0s/buck,darkforestzero/buck,dsyang/buck,artiya4u/buck,JoelMarcey/buck,davido/buck,Distrotech/buck,MarkRunWu/buck,janicduplessis/buck,Heart2009/buck,k21/buck,romanoid/buck,vschs007/buck,liuyang-li/buck,SeleniumHQ/buck,vine/buck,facebook/buck,ilya-klyuchnikov/buck,dpursehouse/buck,pwz3n0/buck,davido/buck,liuyang-li/buck,kageiit/buck,k21/buck,Distrotech/buck,rhencke/buck,janicduplessis/buck,Dominator008/buck,janicduplessis/buck,darkforestzero/buck,nguyentruongtho/buck,tgummerer/buck,rhencke/buck,Addepar/buck,romanoid/buck,vschs007/buck,SeleniumHQ/buck,Dominator008/buck,raviagarwal7/buck,clonetwin26/buck,LegNeato/buck,stuhood/buck,janicduplessis/buck,ilya-klyuchnikov/buck,Learn-Android-app/buck,robbertvanginkel/buck,dsyang/buck,MarkRunWu/buck,davido/buck,Dominator008/buck,Addepar/buck,rhencke/buck,rmaz/buck,marcinkwiatkowski/buck,tgummerer/buck,illicitonion/buck,illicitonion/buck,justinmuller/buck,shybovycha/buck,grumpyjames/buck,lukw00/buck,zpao/buck,siddhartharay007/buck,1yvT0s/buck,bocon13/buck,zhan-xiong/buck,JoelMarcey/buck,neonichu/buck,SeleniumHQ/buck,janicduplessis/buck,Distrotech/buck,zhuxiaohao/buck,robbertvanginkel/buck,pwz3n0/buck,mogers/buck,1yvT0s/buck,mikekap/buck,kageiit/buck,1yvT0s/buck,darkforestzero/buck,kageiit/buck,grumpyjames/buck,zhuxiaohao/buck,k21/buck,pwz3n0/buck,nguyentruongtho/buck,raviagarwal7/buck,stuhood/buck,dsyang/buck,mogers/buck,davido/buck,siddhartharay007/buck,SeleniumHQ/buck,1yvT0s/buck,siddhartharay007/buck,MarkRunWu/buck,raviagarwal7/buck,dpursehouse/buck,mread/buck,tgummerer/buck,Learn-Android-app/buck,liuyang-li/buck,shs96c/buck,dushmis/buck,luiseduardohdbackup/buck,dsyang/buck,daedric/buck,stuhood/buck,ilya-klyuchnikov/buck,robbertvanginkel/buck,zhan-xiong/buck,janicduplessis/buck,ilya-klyuchnikov/buck,grumpyjames/buck,facebook/buck,justinmuller/buck,illicitonion/buck,Learn-Android-app/buck,grumpyjames/buck,raviagarwal7/buck,romanoid/buck,LegNeato/buck,dushmis/buck,illicitonion/buck,vschs007/buck,siddhartharay007/buck,liuyang-li/buck,Learn-Android-app/buck,clonetwin26/buck,janicduplessis/buck,Learn-Android-app/buck,tgummerer/buck,dsyang/buck,pwz3n0/buck,daedric/buck,saleeh93/buck-cutom,Learn-Android-app/buck,stuhood/buck,liuyang-li/buck,mnuessler/buck,daedric/buck,SeleniumHQ/buck,liuyang-li/buck,mikekap/buck,mnuessler/buck,rowillia/buck,mikekap/buck,robbertvanginkel/buck,siddhartharay007/buck,liuyang-li/buck,clonetwin26/buck,ilya-klyuchnikov/buck,grumpyjames/buck,mogers/buck,OkBuilds/buck,darkforestzero/buck,stuhood/buck,grumpyjames/buck,vine/buck,brettwooldridge/buck,mikekap/buck,shybovycha/buck,daedric/buck,artiya4u/buck,rhencke/buck,mnuessler/buck,zhan-xiong/buck,dsyang/buck,MarkRunWu/buck,mnuessler/buck,justinmuller/buck,romanoid/buck,robbertvanginkel/buck,dushmis/buck,mogers/buck,SeleniumHQ/buck,janicduplessis/buck,robbertvanginkel/buck,mikekap/buck,rhencke/buck,pwz3n0/buck,vine/buck,OkBuilds/buck,shs96c/buck,clonetwin26/buck,janicduplessis/buck,LegNeato/buck,clonetwin26/buck,liuyang-li/buck,1yvT0s/buck,rowillia/buck,OkBuilds/buck,brettwooldridge/buck,sdwilsh/buck,zhan-xiong/buck,hgl888/buck,JoelMarcey/buck,ilya-klyuchnikov/buck,daedric/buck,hgl888/buck,shs96c/buck,rowillia/buck,lukw00/buck,daedric/buck,justinmuller/buck,luiseduardohdbackup/buck,LegNeato/buck,Distrotech/buck,hgl888/buck,pwz3n0/buck,Dominator008/buck,romanoid/buck,dpursehouse/buck,Addepar/buck,kageiit/buck,shybovycha/buck,marcinkwiatkowski/buck,illicitonion/buck,Dominator008/buck,mikekap/buck,rmaz/buck,siddhartharay007/buck,tgummerer/buck,mnuessler/buck,janicduplessis/buck,brettwooldridge/buck,vine/buck,Addepar/buck,saleeh93/buck-cutom,mnuessler/buck,MarkRunWu/buck,marcinkwiatkowski/buck,rhencke/buck,kageiit/buck,daedric/buck,luiseduardohdbackup/buck,vine/buck,facebook/buck,Distrotech/buck,Addepar/buck,bocon13/buck,rowillia/buck,grumpyjames/buck,bocon13/buck,darkforestzero/buck,rowillia/buck,sdwilsh/buck,davido/buck,shybovycha/buck,ilya-klyuchnikov/buck,mikekap/buck,illicitonion/buck,rowillia/buck,marcinkwiatkowski/buck,dpursehouse/buck,darkforestzero/buck,vschs007/buck,zhuxiaohao/buck,mread/buck,robbertvanginkel/buck,justinmuller/buck,Dominator008/buck,LegNeato/buck,marcinkwiatkowski/buck,dsyang/buck,shybovycha/buck,k21/buck,raviagarwal7/buck,hgl888/buck,SeleniumHQ/buck,bocon13/buck,brettwooldridge/buck,clonetwin26/buck,facebook/buck,sdwilsh/buck,Learn-Android-app/buck,ilya-klyuchnikov/buck,Addepar/buck,zhuxiaohao/buck,mogers/buck,dpursehouse/buck,illicitonion/buck,lukw00/buck,daedric/buck,dpursehouse/buck,OkBuilds/buck,zhan-xiong/buck,tgummerer/buck,nguyentruongtho/buck,LegNeato/buck,tgummerer/buck,janicduplessis/buck,stuhood/buck,artiya4u/buck,vine/buck,brettwooldridge/buck,sdwilsh/buck,justinmuller/buck,k21/buck,marcinkwiatkowski/buck,zhuxiaohao/buck,Distrotech/buck,Distrotech/buck,vschs007/buck,zpao/buck,OkBuilds/buck,davido/buck,rmaz/buck,JoelMarcey/buck,vschs007/buck,k21/buck,hgl888/buck,artiya4u/buck,luiseduardohdbackup/buck,ilya-klyuchnikov/buck,stuhood/buck,Dominator008/buck,shs96c/buck,pwz3n0/buck,sdwilsh/buck,shybovycha/buck,clonetwin26/buck,robbertvanginkel/buck,Heart2009/buck,OkBuilds/buck,artiya4u/buck,JoelMarcey/buck,vine/buck,Dominator008/buck,mread/buck,OkBuilds/buck,clonetwin26/buck,davido/buck,shs96c/buck,raviagarwal7/buck,robbertvanginkel/buck,rmaz/buck,siddhartharay007/buck,mikekap/buck,artiya4u/buck,lukw00/buck,SeleniumHQ/buck,bocon13/buck,JoelMarcey/buck,vine/buck,shs96c/buck,rowillia/buck,clonetwin26/buck,clonetwin26/buck,zhuxiaohao/buck,mnuessler/buck,zhuxiaohao/buck,tgummerer/buck,shs96c/buck,Heart2009/buck,dushmis/buck,Distrotech/buck,mread/buck,LegNeato/buck,shybovycha/buck,nguyentruongtho/buck,LegNeato/buck,romanoid/buck,liuyang-li/buck,ilya-klyuchnikov/buck,mikekap/buck,artiya4u/buck,mogers/buck,luiseduardohdbackup/buck,davido/buck,rmaz/buck,zhan-xiong/buck,liuyang-li/buck,neonichu/buck,daedric/buck,liuyang-li/buck,sdwilsh/buck,pwz3n0/buck,pwz3n0/buck,zhuxiaohao/buck,rmaz/buck,k21/buck,dushmis/buck,lukw00/buck,daedric/buck,pwz3n0/buck,romanoid/buck,Addepar/buck,1yvT0s/buck,Heart2009/buck,mread/buck,clonetwin26/buck,dushmis/buck,1yvT0s/buck,justinmuller/buck,ilya-klyuchnikov/buck,grumpyjames/buck,SeleniumHQ/buck,rowillia/buck,rmaz/buck,mogers/buck,Dominator008/buck,Addepar/buck,darkforestzero/buck,dsyang/buck,bocon13/buck,lukw00/buck,darkforestzero/buck,Distrotech/buck,dsyang/buck,dsyang/buck,zhan-xiong/buck,facebook/buck,zhan-xiong/buck,justinmuller/buck,zpao/buck,Heart2009/buck,rhencke/buck,rmaz/buck,shybovycha/buck,hgl888/buck,neonichu/buck,MarkRunWu/buck,marcinkwiatkowski/buck,shs96c/buck,k21/buck,zpao/buck,justinmuller/buck,marcinkwiatkowski/buck,dsyang/buck,romanoid/buck,rmaz/buck,romanoid/buck,SeleniumHQ/buck,vschs007/buck,dushmis/buck,sdwilsh/buck,LegNeato/buck,JoelMarcey/buck,rmaz/buck,brettwooldridge/buck,tgummerer/buck,siddhartharay007/buck,k21/buck,rhencke/buck,vschs007/buck,darkforestzero/buck,LegNeato/buck,illicitonion/buck,illicitonion/buck,lukw00/buck,zhan-xiong/buck,rmaz/buck,zhan-xiong/buck,artiya4u/buck,neonichu/buck,brettwooldridge/buck,raviagarwal7/buck,vschs007/buck,rowillia/buck,zhan-xiong/buck,LegNeato/buck,mnuessler/buck,brettwooldridge/buck,OkBuilds/buck,Addepar/buck,ilya-klyuchnikov/buck,Dominator008/buck,illicitonion/buck,brettwooldridge/buck,darkforestzero/buck,romanoid/buck,saleeh93/buck-cutom,justinmuller/buck,shybovycha/buck,neonichu/buck,raviagarwal7/buck,MarkRunWu/buck,mnuessler/buck,rowillia/buck,romanoid/buck,lukw00/buck,vschs007/buck,Heart2009/buck,clonetwin26/buck,Learn-Android-app/buck,shybovycha/buck,hgl888/buck,nguyentruongtho/buck,dsyang/buck,neonichu/buck,shs96c/buck,SeleniumHQ/buck,artiya4u/buck,robbertvanginkel/buck,luiseduardohdbackup/buck,daedric/buck,neonichu/buck,bocon13/buck,mread/buck,sdwilsh/buck,k21/buck,pwz3n0/buck,brettwooldridge/buck,OkBuilds/buck,zhan-xiong/buck