Allow eof instead of eol for comments, closes idris-lang/Idris-dev#503
Some refactoring of bracketed expressions (centralizing most of the
expressions). This provides some simplification for future optimization
of grammar regrding issue idris-lang/Idris-dev#452.
Refactored data declaration to use less lookahead for better errors and
some performance improvement
Refactored constraint syntax to use less lookahead
Changed structure of parser such that it correctly overloads
TokenParsing using some newtype hackery.
Fixed Trifecta version to 1.1 until future versions work again
Merge pull request #506 from ahmadsalim/master

Further work on parser