Remove cabal-ghci support

[gracjan]

cabal-ghci was like cabal-dev. After proper support for 'cabal repl' those are not needed anymore.

[gracjan]

Longer discussion in comments below the issue #198.

[gracjan]

Fixed by #480.

[gracjan]

This was not fully done after all.

[gracjan]

@johnwalker: And if you could finish removing cabal-ghci that would be awesome!

[johnwalker]

sure!