patch applied (packages/polyparse): Make several combinators lazier, in the PolyLazy variation only.

[Malcolm Wallace]

Mon May 14 09:53:50 PDT 2007  Malcolm.Wallace at cs.york.ac.uk
  * Make several combinators lazier, in the PolyLazy variation only.
  The combinators are: discard, exactly, many, many1, bracket.
  Now, they can return a prefix of their resultant data-structure,
  before seeing the end of it.

    M ./src/Text/ParserCombinators/PolyLazy.hs -15 +14