pipes-parse and pipes-attoparsec

I'm putting this pull request here in case you want to try it yourself until I try again, since currently it doesn't build for me using `cabal-meta`, so I'm not certain my changes are OK. However, `tonyday567/pipes-ecosystem/master` also doesn't build in my computer, so perhaps the problem is unrelated to these new changes.

(edit: moved some useless comments to issue #3)