Decouple parser and lexer generation

[zaach]

Currently Jison generates both parser and lexer at the same time. Once it is possible to combine commonjs modules easily, parser and lexer modules could be generated separately and combined only when needed.

An easy way to combine commonjs modules would also allow the generic parser module to be decoupled from parse tables. Then, only the parse table would be necessary output of the generation process; the parser module could simply require the needed parse table.

[zaach]

fixed