- Properly handle DataBlocks with optional fields at end;
- Fix a few field dissections;
General code cleanup;
- Remove almost all tests using tvb_length_remaining():
If there's not enough data available, just let an
exception be thrown.
- Fix a memory leak;
- Simplify code in various places.
- Add a reference to the (a ?) Microsoft spec for RDP.
Fixes Bug #7862 in a more complete manner than SVN #45566.