Update INSTALL.md
Update INSTALL.md

Former-commit-id: b792bb869860dac3302420bf5f968959e2dd3181
clab/dynet,clab/dynet,clab/dynet,shuheik/dynet,xunzhang/dynet,shuheik/dynet,clab/cnn,clab/cnn,danielhers/dynet,danielhers/dynet,danielhers/dynet,danielhers/dynet,clab/dynet,chunyang-wen/dynet,shuheik/dynet,chunyang-wen/dynet,clab/dynet,xunzhang/dynet,shuheik/dynet,shuheik/dynet,clab/dynet,clab/cnn,shuheik/dynet,chunyang-wen/dynet,danielhers/dynet,shuheik/dynet,xunzhang/dynet,danielhers/dynet,chunyang-wen/dynet,xunzhang/dynet,danielhers/dynet,clab/dynet