Fixed: Methods viewDidMoveToSuperview viewDidMoveToWindow viewWillMoveToSuperview viewWillMoveToWindow not called as in Cocoa

Previously, when adding, removing, replacing a CPView, the framework didn't call the methods viewDidMoveToSuperview, viewDidMoveToWindow, viewWillMoveToSuperview and viewWillMoveToWindow as in Cocoa. Now it does.

The main change is that these methods will be called when removing a CPView.

Added unit-test in Tests/AppKit/CPViewTest.j
I just improved this part. We only call `_setWindow:nil` when adding a view to a view without a window where the previous superview had a window.