update lz4 to r119
Merge pull request #24 from craigcarnell/update-lz4

update lz4 to r119
update folly hash to latest
unbreak the build by defining FOLLY_VERSION
remove a file from the folly build

The functions defined here conflict with things built in to libstdc++.

Since we don't use this file in HHVM anyway, removing this prevents
duplicate symbols when statically linking.
Merge pull request #25 from danslo/static-linking

remove a file from the folly build