Add annotations

Also how to do radio buttons (option-groups) in UI.
Changed help a little
I did not implement any more code when adding metric radiobutton. I have left that to you and how you want to handle Module/CP data.

What do you thiink about using more usual values when specifying gear creation.
I got my info from here:
http://www.gizmology.net/gears.htm

re the positioning of a second meshing gear:
- I think first gear tooth is directly to right.
- So a meshing gear would be one full tooth rotation down around gear center. 
- Should mesh everytime (odd or even teeth)