Patch to make ghc-mod compile with >=monad-control-1.*

See https://github.com/kazu-yamamoto/ghc-mod/issues/422
Upstream has changed version to 0.0.0

See commit d0e1ac9d9fdf1ee40232ee4e634e5962afc43ded
Bump ghc-api to 7.8.4
Add binary-0.7.1 for ghc-api-7.8.4 to work correctly

Also added CABAL_CORE_LIB_GHC_PV for ghc-7.8.4
Merge pull request #380 from rabisg/ghc-7.8.4

Miscellaneous changes required for ghc-mod with ghc-7.8.4