Improve Transformation API
Add 'width' and 'height' properties to JPEGImage
Include jmorecfg.h from libjpeg8 distributon
Use bytearray instead of str for image data
Add support for EXIF orientation and thumbnail

* On rotation, EXIF orientation will be set to 1 (normal)
* EXIF data is now maintained during all operations except scaling
Add 'exif_autotransform' method to transform according to EXIF data
Do not cache width and height
Rename 'scale' to 'downscale' and abort if size is larger than original
Docstrings for JPEGImage
After transformations, return new image object instead of self
Improved error checking
Add tests
Fix Python 2.6 and 3.3