Changed default shortcuts as suggested by David Revoy

This patch fixes most of the shortcuts mentioned in the bugreport except:

"Save As..." -- this is a standard KDE shortcut, so you can configure
                with a Configure Desktop dialog

"Fullscreen" -- this is a standard shortcut as well, but you can't easily
                set it to "Ctrl+F" due to bug 313621 in KDE shortcuts
                system.

BUG:313217
CCBUG:313621