Initial GHC 7.6.3 package

This installs GHC successfully on its own, but lacks the rest of the haskell ecosystem (ie, Cabal as a package manager).

I don't see any way to make multiple distinct packages get installed as a single install, so I imagine that you'll have to run a few commands in a row to get a full environment. It'll be:

```
parts install ghc
parts install cabal
```

The other gotcha is that it requires more ram & disk space than the free level allows. I don't see much of a way around that unfortunately.

Next up is cabal...