Timeline bug fixes

The full documentation for the timeline window is now live as well as the following fixes:

Fixes

• Fixed some text in settings window
• Fixed track right-click options going behind menu bar
• Fixed issue with loading multiple tracks showing wrong track
• Fixed an issue with color depth for gif export
• Fixed a bug with panning horizontally in the timeline (shift+click)
• Fixed an issue where track duplicate would use currently selected track rather than right-clicked track