Translated to Haskell

Initial commit of a broad-strokes translation to Haskell.

To use:
$ cabal sandbox init
$ cabal install --only-dependencies
$ mkdir output
$ cabal build && cabal run -- path/to/image.ext

What's done:
* Quadtree algorithms implemented
* Input & kludged output via JuicyPixels
* Renders leaves as solid-colored squares, but can be easily updated
  by defining new functions of type `Quad -> Image r`
* Works in parallel (kind of), run with command line args `+RTS -N`

TODO:
* Fix awful output hack
* Clean up interface
* Handle gif-making through JuicyPixels
* Consider optimizations (histograms will probably be high value)
* Implement alternative rendering modes
* Refactoring, particularly with regards to imports
* Focus on parallelization (add back `-fllvm` compilation flag to start)