update folly to hash to point to 12:0 and help fix the HHVM OSS build
Update folly submodule to version 13:0
Enable folly/LifeSem.cpp and folly/detail/Futex.cpp build.

These used to not build right, but they seem okay now.
Needed for asio thread manager.
Enable folly/detail/MemoryIdler.cpp build.
Bump thrift to 12:0
Revert "Bump thrift to 12:0"

This reverts commit 4e1c7368825b91e8e5f03df331a4ec7811115d4a.

We won't be ready to use newer thrift until proxygen gets updated. :(
submodules moved to fork github.com/hhvm-osx