v2.14.1 update, rendering of minimal complete definitions for source files.

These add some really neat usability features that would be great to get into 7.8, especially to promote the existence of the MINIMAL pragma.

I spoke with @hvr and he said this can be included in 7.8.1, he will happily update the ghc-7.8 to whatever is on our v2.14.

Nonetheless, I've bumped the version to haddock-2.14.1 since haddock-2.24.0 was already tagged.