v3.2.0 more pixels!

Change Log

# Added

• Added "fill" tool for tilemap
• Added non-destructive mode in tilemap files, different click to cancel current drawing
• Added undo/redo support for tilemap

# Fixed

• Can't select color in ``Active Colors`` Palette! Fixed
• Can't zoom in or out when selecting gradient tool! Fixed
• Pen drawing effect other tilemap files when  switching between them! Fixed

# Changed

• Better tool visualization in tilemap file(red square for eraser, clearer tool thumbnail & clearer tool rendering)
• Tile sources names in tilemap is pixelated!