New basic architecture implemented.
Delete EditorBackend.hs

old editor file
Delete Menu.hs

old editor file
Delete EditorBackendTest.hs

old editor file
Delete Main.hs

old editor file
Delete Execute.hs

old editor file
some corrections in architecture
Editors architecture to docu
additional comments
some comments updated
Refactor Editor: fill TextAreaContent.hs
New archetecture for window and its elements.
created Highlighter.hs, added import in TextArea.hs
Merge remote-tracking branch 'origin/NewEditor' into highlighter
Also changed lots of stuff...

[skip ci]
Conflicts:
	src/RailEditor/Highlighter.hs
	src/RailEditor/TextArea.hs