Update v1.0.3 - Outline Brush, RGB Shift & Selection

With this update a few new options are introduced - you can now outline as you draw with the Outline Brush, paint your own selection, shift colors in the RGB color model, and enjoy Magic Pencil without crashing Aseprite.

Changes:

• [Improvement] Added an option for the Outline Brush, the original Outline option is now renamed to Outline Tool, suggested by @apoonto
• [Improvement] Added an option to shift colors in the RGB color model
• [Improvement] Added an option for the Selection
• [Improvement] Lift now creates a layer directly above (with left-click) or below (with right-click) the current one
• [Fix] Undoing last action (Ctrl+Z) with mouse over Magic Pencil dialog no longer crashes Aseprite
• [Fix] Magic Pencil no longer unlinks linked cels, reported by @stahli_25