Support EXIF orientation for network JPG/TIFF

Uses commons-imaging to determine orientation (only if it's on the classpath, it's an optional dependency).  Tests intentionally omitted for now, happy to add them if you want this feature.

Since commons-imaging is still at 1.0.0-SNAPSHOT I had to temporarily add the Apache snapshot repository but this API hasn't changed since it was brought into commons.
These don't have constants?