v1.2 - Major update - Free masks

- Added: Color picker
- Added: Free masks
- Added: Export animation as pre-rendered images
- Added: Different tool sizes
- Added: Brush modes
- Added: FPS independent drawing
- Added: More tooltips & hotkeys
- Added: Frame exceed warning
- Added: Asset type import warning
- Added: Auto render

- Bugfix: Minimizing/Resizing the window causes the animation preview to display incorrectly

- Set export asset default name to asset tab name
- Replaced mask editor bg color options with color picker window
- Changed help pages

- Code optimizations