OpenJPEG option. Closes #61

Fixes bug where scales weren't being used.
Introduces AbstractJP2Transformer.
PIL always does rotation.
Makes a bunch of static methods instance. None are a big deal because the app only has one instance of the class. Makes code more readable.
Updates docs re OPJ, added license.
setup.py uses whichever jp2lib is configured
Add OpeJpeg libraries/executable