clean up .cabal file
remove no longer needed displayModule function
Merge branch 'master' of github.com:diagrams/diagrams-haddock
deleting lots of code, hooray!

We don't need this ParsedModule stuff anymore, or CommentWithURLs,
that was all only necessary for exact-printing back out via HSE.  Now
we just pull out some diagram URLs and code blocks and be done with it.
export utility functions