Updated install section of haskell readme
set haskell-process-type to auto

Should work in more use-cases
Removed ghci-completion package

- ghci-completion is redundant when using flycheck-haskell
Use "magit-ido-completing-read" for completion.

Provides better completion throughout Magit.
Best used together with: "(setq magit-repo-dirs '("~/git/"))".