Implement native ruby parser

[flbulgarelli]

Although Ruby support #59 has been implemented externally, it would be nice to actually have a Haskell parser, which may be faster, simpler to use, and may be bundled within the JS distribution, making it more portable.

The bad news is that there is no Language.Ruby package over there. The good news is that https://github.com/whitequark/parser seems to be implemented using yacc - https://github.com/whitequark/parser/blob/master/lib/parser/ruby23.y - and that happy - which we are indirectly using with some of our own parsers - is inspired on it, so perhaps porting the BNF may not be that difficult nor a complete rewrite.

[flbulgarelli]

Also, we could get rid off that ugly warning @julian-berbel https://github.com/whitequark/parser/issues/286 :stuck_out_tongue:

[flbulgarelli]

This issue is in-progress here: https://github.com/flbulgarelli/language-ruby

[luchotc]

Can we close this one and move the specific issues to that repo? @flbulgarelli @julian-berbel

[flbulgarelli]

Nope, since even after implementing that parser, we will have to integrate it into mulang.