2 Legit 2 Quit

The current (master) version of ObjectiveHaskell was mostly a proof-of-concept. It worked, and it was cool, but I had bigger fish to fry for quite a while. Now, I want it to become a Real Boy.

**Major changes:**

 - [x] Replace prebuilt xcconfigs with dynamically generated ones that use the correct GHC paths for the user's system. _See `script/genconfig`._
 - [x] Dynamically find GHC for build scripts, instead of hardcoding one location.
 - [x] Replace crappy per-file compilation script (which just did `--make` anyways) with a Run Script build phase. _See `script/hsbuild`._
 - [x] Automatically build a static library that includes all Haskell dependencies, so users don't have to add fragile linker flags for each package (and version). _Part of `script/hsbuild`, using `script/flagsForPackage.hs`. Eventually this will use `-library` from GHC._
 - [x] Remove demo project, to be replaced later with something better.
 - [ ] Get rid of the `Model`/`OHModel` stuff. It's awful.
 - [ ] Remove Template Haskell code from modules that shouldn't require it. If `ghc-ios` supports Template Haskell now, this can be skipped.
 - [ ] Clean up Haddock and code style.
 - [ ] Update README.

@mchakravarty @lukexi @maxpow4h @jonsterling