Added instructions for ClangFormat installation and editor integration.
Added instructions for ClangFormat installation and editor integration.

Review: https://reviews.apache.org/r/29233

verizonlabs/mesos,chhsia0/mesos,Gilbert88/mesos,chhsia0/mesos,neilconway/mesos,Gilbert88/mesos,reneploetz/mesos,zmalik/mesos,asamerh4/mesos,andschwa/mesos,jpeach/mesos,neilconway/mesos,craimbert/mesos,reneploetz/mesos,Aman-Jain-14/customizedMesos,chhsia0/mesos,dforsyth/mesos,gsantovena/mesos,yuquanshan/customizedMesos,asamerh4/mesos,dforsyth/mesos,gsantovena/mesos,verizonlabs/mesos,craimbert/mesos,Gilbert88/mesos,abudnik/mesos,yuquanshan/customizedMesos,neilconway/mesos,reneploetz/mesos,reneploetz/mesos,abudnik/mesos,andschwa/mesos,yuquanshan/customizedMesos,verizonlabs/mesos,kaysoky/mesos,zmalik/mesos,andschwa/mesos,chhsia0/mesos,abudnik/mesos,jpeach/mesos,dforsyth/mesos,neilconway/mesos,abudnik/mesos,verizonlabs/mesos,andschwa/mesos,andschwa/mesos,verizonlabs/mesos,jpeach/mesos,kaysoky/mesos,andschwa/mesos,Aman-Jain-14/customizedMesos,yuquanshan/customizedMesos,reneploetz/mesos,jpeach/mesos,zmalik/mesos,kaysoky/mesos,Gilbert88/mesos,asamerh4/mesos,reneploetz/mesos,chhsia0/mesos,kaysoky/mesos,craimbert/mesos,kaysoky/mesos,Aman-Jain-14/customizedMesos,jpeach/mesos,dforsyth/mesos,yuquanshan/customizedMesos,asamerh4/mesos,gsantovena/mesos,Aman-Jain-14/customizedMesos,Gilbert88/mesos,kaysoky/mesos,reneploetz/mesos,asamerh4/mesos,jpeach/mesos,gsantovena/mesos,neilconway/mesos,zmalik/mesos,gsantovena/mesos,yuquanshan/customizedMesos,Gilbert88/mesos,abudnik/mesos,dforsyth/mesos,craimbert/mesos,jpeach/mesos,chhsia0/mesos,andschwa/mesos,dforsyth/mesos,neilconway/mesos,Aman-Jain-14/customizedMesos,Aman-Jain-14/customizedMesos,Gilbert88/mesos,chhsia0/mesos,zmalik/mesos,zmalik/mesos,asamerh4/mesos,neilconway/mesos,craimbert/mesos,craimbert/mesos,gsantovena/mesos,Aman-Jain-14/customizedMesos,craimbert/mesos,abudnik/mesos,asamerh4/mesos,zmalik/mesos,gsantovena/mesos,yuquanshan/customizedMesos,dforsyth/mesos,verizonlabs/mesos,verizonlabs/mesos,kaysoky/mesos,abudnik/mesos