Merge pull request #2 from 7shi/master

make a ffi version translator
Add ffi module
Add ffi bftranslate for mac
integrate bftranslator-ffi and bftranslator-ffi-mac
support indent for bftranslate-ffi
change comment for bftranslate-ffi: /* x */ -> // x
use 'for' instead of 'while' in bftranslate-ffi