Use ppa:boost-latest for latest Boost version
Use ppa:boost-latest for latest Boost version


Former-commit-id: cff8534b3741210e3602a570c8b87843e1ccae97
clab/cnn,clab/dynet,clab/cnn,xunzhang/dynet,clab/dynet,xunzhang/dynet,chunyang-wen/dynet,xunzhang/dynet,shuheik/dynet,shuheik/dynet,chunyang-wen/dynet,clab/dynet,danielhers/dynet,shuheik/dynet,clab/cnn,danielhers/dynet,shuheik/dynet,clab/dynet,danielhers/dynet,xunzhang/dynet,chunyang-wen/dynet,shuheik/dynet,shuheik/dynet,clab/dynet,danielhers/dynet,clab/dynet,clab/dynet,danielhers/dynet,danielhers/dynet,shuheik/dynet,chunyang-wen/dynet,danielhers/dynet