Tiler

This is of course not ready to merge yet, but I thought I'd start the pull request so we can discuss it. I really don't know what I'm doing in Node, Coffee, or Streamline, so feel free to critique all of it.

This branch requires you to have [ImageMagick](http://www.imagemagick.org/script/index.php) installed. If you're on Mac, this should be:

```
brew install imagemagick
```

I had some trouble with it at first, evidently because my ImageMagick was out of date. `brew upgrade imagemagick` did the trick.

Still to do:

- [ ] Update readme for this new dependency
- [ ] Remove deepzoomtools dependency
- [ ] Pipe the API into it
- [x] Image pyramid
- [x] Write out DZI XML
- [ ] Break into tiles