shortcut key to center current marker(s) in camera views at current zoom level

[Dave Baier]

Would like to be able to re-center the camera views when the currently tracking marker or markers go out of view while maintaining the zoom level

[Benjamin Knorlein]

fixes #115 : 'C' Key focuses the camera views on the currently selected marker

→ <<cset 1c3bb8a0aab6>>