Changes/Fixes:
- Fixed several VGM issues (incorporated some from Perkka too)
- Current song is now selected by default in export dialog
- Added VRC7 sustain bit (override release) in NSF
- Added sub-menus for context menus and moved scale options to them
- Added option for dim unsupported channels
- Added option to make selected patterns unique (icons should follow in a major release)
- Fixed issue with N163 loop / release points on import (bug introduced in 4.5.0)
- Fixed FamiTracker N163 export issues (chunk length and truncate to 32)
- Fixed some export dialog localisation errors