Enhanced the rotate images dialog:

- The dialog shows information on the axes.
- An overlay is used to visualize the axes.

Signed-off-by: Michael Entrup <entrup@arcor.de>
Added more comments:

* I added some more block commends and placed all line commends behind the
commented command.
* I use the 2nd Degree Polynomial predefined by ImageJ instead of my own
function.

Signed-off-by: Michael Entrup <entrup@arcor.de>