Complete re-factoring. Embedding for PNG and JPEG is now standard-compliant. Initialization from headers, WCS objects, and images is now done via class methods (see README.md).
0.1.4
Now write XMP packet using ElementTree to ensure XML compliance
0.1.3
Rewrote XML parsing using ElementTree. Compact XMP tags are now read properly. All example images parse without errors.
0.1.2
Added support for embedding AVM meta-data in TIF files
0.1.1
Added support for embedding AVM meta-data in JPG and PNG files, and added methods to create AVM container from WCS or FITS header information.