Fix the shortcut handling with KKeySequenceWidget, thanks to the new validate stuff from kdelibs.

I disabled the ability to override conflicting shortcuts, as it did not work and I did not find a way to actually disable a shortcut of a conflicting action.

Also, I added some todos to do more shortcut checking, currently conflicts against global shortcuts and such are not checked.

Also, remove some tabs and fix 2 deprcated functions.