Actionscript 2 class.
This class enriches existing text fields with

1. undo/redo via keyboard and context menu
2. associates a passed function to the onChanged event
3. adds additional context menu items if passed

known bugs:

1. the undo has one step too much
2. the text field cannot reside directly under _level0
3. Keyboard shortcuts do not work under MacOs

• documentation
• rewrite undo/redo
• licence