Merge pull request #60 from Wohlstand/master

Merge to Update 60
Merge pull request #61 from Wohlstand/master

Merge to Update 61
Add Layer Change history
Add history for change Water <-> Quicksand [Enviroment Type]
Dummy change
Memory Leaks on BG optimisation
Merge pull request #62 from Wohlstand/master

Merge to Update 62
oops, forgot to record history for layer at other items
Merge branch 'master' of https://github.com/KevinW1998/PlatGEnWohl.git
Spelling fix
Merge pull request #63 from Wohlstand/master

Merge to Update 63
Merge pull request #48 from KevinW1998/master

Some History Changes: Layer + Water <-> Quicksand
Small memory leaks fixing
[Experimental] Preparing for new DrawBG algorithm
Add Template for Drag and Drop Layer
Merge pull request #64 from Wohlstand/master

Merge To Update 64
Merge pull request #49 from KevinW1998/master

Add Template for Drag and Drop Layer
Small update in SubWindow's function
small change
Anti Memory leaks small update