Merge pull request #439 from HerbertV/master

Added a lot of sprite variants see issue #393
Possible fix for #409
change mask text #416
Lots of clipboard, undo and world file changes. This unifies saving and loading procedures.
Fix for schematic v2.
fix for schematics part 2
Merge pull request #1 from BinaryConstruct/master

Merge From  BinaryConstruct:master