Editor Refactoring

Refactoring the editors' code. Introduced a new superclass for them providing a toolbar.
This is a try to make the code somewhat maintainable, but there's just so much done wrong there, it's still a long way.
Sure, I'll do some style updates sooner or later ;) I think you renamed that particular enum in `lmms2` already.

Btw, I suggest dropping the convention about parentheses being followed/preceded by a space character (like `printf( "Hello World!" );` instead of `printf("Hello World!");`). It can get really hard to stick to, and it doesn't really add much to readability.