Read flymake options from .ghci file

I've added a bit of code to Check.hs that reads the warning flags from a local .ghci file and uses those rather than the default flags.  I like to see flymake mark the same warnings that I get in ghci.

My changes are in the local branch.  The master branch is identical to yours.

There are a couple of other changes, too.  I added some dependencies to the ghc-mod.cabal file, and included a small bugfix in ghc-flymake.el.  At least I think it's a bugfix.  It may just remove some functionality that I don't know about.

I hope this is of interest to you,
-Rod