[GSOC-UPDATE] Impress Remote

[Andrzej J. R. Hunt]

Hi all,

Some more updates:

- Image export code (preliminary version with temporary files) and 
transfer working
- Image decoding/display working, but highly temperamental.
- Improved protocol implementation on java side to correctly read messages.
- XSlideShowListener implemented (and namespace problems discovered + 
fixed ).
- Fixed licence headers (accidentally lost due to incorrect git stashing).

Cheers,
Andrzej