2D Binpacking
jsyang.ca@gmail.com

Not much to say: packing algorithm is shelf-based,
pre-sort the rectangles and use descending height,
if you can't fit the width of the current rect onto
the current shelf, create a new shelf.

Implemented from the tutorials:
http://users.cs.cf.ac.uk/C.L.Mumford/heidi/BinPacking.html