Extract IMouseListener

[nk-coding]

Steps to extract an IMouseListener (as requested in #475):

1. Add an interface IMouseListener with all the relevant methods from MouseListener
2. Add an IMouseListener entry on TYPES (or reuse or replace the existing MouseListener one)
3. Update MouseTool
   • either additionally inject TYPES.IMouseListener or update the existing TYPES.MouseListener (depending on the chosen option from 2.)
   • Replace MouseListener by IMouseListener basically everywhere in this class

I personally would probably chose the "replace TYPES.MouseListener" option on the next major release, as this is imho the cleanest one