We might avoid some temporaries
We might avoid some temporaries

Summary:
It seems we might avoid temporaries.  To do so we pass arguments
directly to constructors with the help of emplace_back member.

Test Plan:
all folly/tests, make check for 37 tests, passed.

Closes https://github.com/facebook/folly/pull/150

Reviewed By: ldbrandy@fb.com

Subscribers: lins, anca, folly-diffs@, yfeldblum

FB internal diff: D1912505

Signature: t1:1912505:1426268158:086882bb53f3d79c3f3b7b2c362318f09b5ee3be

guker/folly,loverszhaokai/folly,mqeizi/folly,romange/folly,colemancda/folly,bsampath/folly,clearlylin/folly,juniway/folly,loverszhaokai/folly,reddit/folly,bikong2/folly,loversInJapan/folly,hongliangzhao/folly,clearlylin/folly,bobegir/folly,doctaweeks/folly,CJstar/folly,clearlinux/folly,stonegithubs/folly,xzmagic/folly,floxard/folly,sonnyhu/folly,lifei/folly,bowlofstew/folly,stonegithubs/folly,ykarlsbrun/folly,CJstar/folly,clearlylin/folly,bobegir/folly,facebook/folly,chjp2046/folly,SeanRBurton/folly,bsampath/folly,Hincoin/folly,gavioto/folly,renyinew/folly,tomhughes/folly,upsoft/folly,floxard/folly,juniway/folly,fw1121/folly,yangjin-unique/folly,SeanRBurton/folly,zhiweicai/folly,clearlinux/folly,theiver9827/folly,nickhen/folly,guker/folly,nickhen/folly,project-zerus/folly,tomhughes/folly,Orvid/folly,alexst07/folly,chjp2046/folly,kernelim/folly,charsyam/folly,SeanRBurton/folly,doctaweeks/folly,nickhen/folly,nickhen/folly,renyinew/folly,Orvid/folly,tomhughes/folly,loversInJapan/folly,colemancda/folly,clearlylin/folly,chjp2046/folly,facebook/folly,SammyK/folly,PPC64/folly,chjp2046/folly,loverszhaokai/folly,shaobz/folly,kernelim/folly,alexst07/folly,KSreeHarsha/folly,zhiweicai/folly,Hincoin/folly,raphaelamorim/folly,SeanRBurton/folly,alexst07/folly,Orvid/folly,wildinto/folly,leolujuyi/folly,upsoft/folly,Hincoin/folly,bobegir/folly,gavioto/folly,reddit/folly,sakishum/folly,KSreeHarsha/folly,Hincoin/folly,loverszhaokai/folly,bsampath/folly,reddit/folly,yangjin-unique/folly,nickhen/folly,cole14/folly,clearlinux/folly,romange/folly,raphaelamorim/folly,sakishum/folly,gavioto/folly,shaobz/folly,lifei/folly,mqeizi/folly,gaoyingie/folly,brunomorishita/folly,KSreeHarsha/folly,renyinew/folly,PPC64/folly,project-zerus/folly,gavioto/folly,mqeizi/folly,floxard/folly,leolujuyi/folly,sakishum/folly,loverszhaokai/folly,stonegithubs/folly,sakishum/folly,wildinto/folly,doctaweeks/folly,facebook/folly,colemancda/folly,yangjin-unique/folly,hongliangzhao/folly,ykarlsbrun/folly,leolujuyi/folly,Eagle-X/folly,SeanRBurton/folly,alexst07/folly,kernelim/folly,bsampath/folly,xzmagic/folly,gavioto/folly,PoisonBOx/folly,constantine001/folly,guker/folly,sonnyhu/folly,charsyam/folly,theiver9827/folly,xzmagic/folly,Eagle-X/folly,rklabs/folly,project-zerus/folly,brunomorishita/folly,colemancda/folly,PoisonBOx/folly,SammyK/folly,loversInJapan/folly,lifei/folly,theiver9827/folly,KSreeHarsha/folly,fw1121/folly,bsampath/folly,PoisonBOx/folly,raphaelamorim/folly,reddit/folly,leolujuyi/folly,arg0/folly,renyinew/folly,stonegithubs/folly,guker/folly,PoisonBOx/folly,fw1121/folly,CJstar/folly,hongliangzhao/folly,loversInJapan/folly,cole14/folly,bikong2/folly,facebook/folly,Hincoin/folly,wildinto/folly,rklabs/folly,reddit/folly,bobegir/folly,renyinew/folly,constantine001/folly,zhiweicai/folly,zhiweicai/folly,brunomorishita/folly,bowlofstew/folly,PoisonBOx/folly,tempbottle/folly,theiver9827/folly,juniway/folly,gaoyingie/folly,gaoyingie/folly,brunomorishita/folly,bowlofstew/folly,facebook/folly,rklabs/folly,brunomorishita/folly,romange/folly,arg0/folly,raphaelamorim/folly,fw1121/folly,Orvid/folly,theiver9827/folly,chjp2046/folly,wildinto/folly,lifei/folly,bowlofstew/folly,romange/folly,KSreeHarsha/folly,upsoft/folly,PPC64/folly,shaobz/folly,cole14/folly,mqeizi/folly,loversInJapan/folly,colemancda/folly,hongliangzhao/folly,bikong2/folly,tempbottle/folly,arg0/folly,sonnyhu/folly,constantine001/folly,xzmagic/folly,ykarlsbrun/folly,kernelim/folly,juniway/folly,doctaweeks/folly,clearlinux/folly,ykarlsbrun/folly,tomhughes/folly,ykarlsbrun/folly,SammyK/folly,shaobz/folly,Eagle-X/folly,PPC64/folly,arg0/folly,floxard/folly,tomhughes/folly,juniway/folly,sakishum/folly,clearlylin/folly,rklabs/folly,clearlinux/folly,gaoyingie/folly,project-zerus/folly,SammyK/folly,Eagle-X/folly,bikong2/folly,lifei/folly,SammyK/folly,upsoft/folly,guker/folly,leolujuyi/folly,xzmagic/folly,hongliangzhao/folly,bowlofstew/folly,charsyam/folly,floxard/folly,mqeizi/folly,constantine001/folly,sonnyhu/folly,CJstar/folly,CJstar/folly,Orvid/folly,rklabs/folly,bikong2/folly,bobegir/folly,kernelim/folly,romange/folly,cole14/folly,alexst07/folly,fw1121/folly,wildinto/folly,tempbottle/folly,tempbottle/folly,yangjin-unique/folly,arg0/folly,shaobz/folly,upsoft/folly,project-zerus/folly,doctaweeks/folly,Eagle-X/folly,constantine001/folly,cole14/folly,stonegithubs/folly,zhiweicai/folly,sonnyhu/folly,yangjin-unique/folly,tempbottle/folly,raphaelamorim/folly,charsyam/folly,gaoyingie/folly,PPC64/folly