Javadoc, Refactorings, new Exporter, and Bug-Fixes

Have another pull-request!

This time including:
- Refactored Image Import/Export classes. (Now they all got their own classes)
- Added a new fancy compressed binary image exporter (ZBIN instead of BIN).
- Generated a nice and fancy javadoc for the entire project.
- Fixed a FATAL bug in the TGA exporter!