equality GADT is now in base, use that

also bump the version
last released version
M-x whitespace-cleanup
reexport (:~:)
typo
Add missing clause to 'patchL'

It is present in the thesis' Agda version but
also dropped in the Haskell version, which was
the basis for the 'gdiff' library.

As explained in the thesis, patchL is not total
but this clause was strictly necessary to work
at all.
Typo in haddocks
add github links
maintain a consistent look
modernize library layout
surely ADT is meant here
grammar fix
Merge pull request #1 from ggreif/master

equality GADT is now in base, use that