Editor: Making the rotate right button work.
Editor: Making the rotate left button work.
Editor: Adding some explanation to the new functions
Merge pull request #529 from arthurbenemann/issue507

Mission Re-Ordering
Editor: Fix bug which was introduced at #529

There was a Array exception because the way our pointers where being updated. To reproduce select a single item and move it to the top of the mission, the next move up (which shouldn't do nothing) caused the exception.
Merge pull request #530 from arthurbenemann/FixFor529

Editor: Fix bug which was introduced at #529