Helppatch: put camera instructions in Handling

the hint '-mousewheel to zoom, right drag to pan' was in the Source
Window section, it is now in the Handling section.

This is because zooming was only available in the Source Window, but now
it's also available in Destination Preview Window.
Merge branch 'master' of https://github.com/vvvv/badMapper
bad scroll value in helppatch
Merge pull request #12 from DominikKoller/master

Helppatch: put camera instructions in Handling