hhvm --devel, removed depends homebrew/dupes

Run cleanup:
- brew remove folly jemallocfb boostfb hhvm-third-party
- brew cleanup -s --force
- brew prune

- homebrew upsteam gcc 4.9 (gcc.rb)
- removed depends homebrew/dupes
- add --devel version snapshot
- more security C/CXX flags, work only upstream --devel version
facebook/hhvm#3808  facebook/hhvm#3844