Upgrade to GHC 8.0.2

[ChrisCoffey]

This sets up a Stack build for dash-haskell and upgrades it to run on GHC 8.0.2 projects. I've been able to successfully test this on ghc-8.0.2 itself:

Yetti> dash-haskell (master) $ dash-haskell ghc-8.0.2
using package db stack:
 > ghc distribution (global db)
 > system user

processing: ghc-8.0.2
  writing files..
  writing plist..
  populating database..
  finished populating sqlite database..

This addresses #18