Protect against streaming mode, and add in partly implemented untested DES parsing.
Add initial support for graphic segment parsing
Add SCOLOR support
Add SBND2 support
Complete basic graphic segment parsing
Add support for XBAND parsing

Also fixes a bug related to COMRAT parsing for downsampled JPEG, found during implementing XBAND.
Initial work on TRE parsing.
Handle case where there is no TRE key in the XML (just need to skip over it)
Major refactoring of TRE parsing and handling.