KeyScroller : Swittching to a Timer instead of a DispatcherTimer

The timer often has to Invoke its call on the NoFocusThread. therefor, it is likely to trigger deadlocks (when scrolling occurs while moving bound windows from different threads).
The Timer (from System.Timers) is created on another thread, so we completely avoid the deadlock problem.
We can now dock windows from different threads and move them around without any deadlocks
Merge branch 'f-roadmap-2013' into f-multithread-fixes
adapted UnbindButton move
Updated csproj and fix minimize UnbindButton
Merge branch 'f-multithread-fixes' into f-roadmap-2013

Conflicts:
	Plugins/Accessibility/CK.WindowManager/WindowManagerExecutor.cs