User should be able to exit full screen map mode via Esc key

[tas50]

Currently the only way to escape the full screen map mode is to either know the key command users to enter / exit the mode, or to quit kismac. It seems much more logical to use the Esc key to exit the full screen mode as most modern applications do.

[McLovin]

+! for this.

For the benefit of anybody arriving here from Google, like I did, it's Command-Shift-F.