Adds mapM to StreamT

mapM threads a per-element monadic effect through the stream
fix CompositionApplicativePlus
Merge pull request #364 from xuwei-k/fix-CompositionApplicativePlus

fix CompositionApplicativePlus
Merge pull request #363 from nuttycom/topic/streamt_mapm

Adds mapM to StreamT
fix typo
Merge pull request #367 from xuwei-k/curried-typo

fix typo