Mapart-Helper 0.11.3

0.11.2 was released with some critical issues and a few unpleasant ones. This patch should fix the detected problems.
I apologize for not finding them earlier

Fixes and minor changes

• Improved Waves staircasing style for images with transparency
• Fixed 2D staircasing style not working entirely;
• Fixed Valley staircasing style for images with transparency;
• Fixed image reset if all colors from the preset were excluded;
• Fixed an exception when sending a message about saving NBT;
• Fixed a warning about exception in logs if the game was closed without opening the Mapart Editor screen;