First pass implementation

I based this code off of this: http://web.archive.org/web/20050306011057/http://www.drmay.net/octree/

It seems to work for lower tree depths - anything more than about 6 and the pictures get washed out - I think it might be the uint32's overflowing. Need to write some tests for that.

Also the public API is probably too large. But works for me!