New: Added support for scaling in CPView

This PR adds the support of scaling in CPView.
There are two new public methods in CPView : -(void)scaleUnitSquareToSize: and -(void)setScaleSize:
-(void)scaleUnitSquareToSize: works exactly as in COCOA, it means if you set a first scale to 0.5 and then 0.5 again, the scaleSize of the view will be 0.25
-(void)setScaleSize: works with the value given. If you set 0.5 after you just seted 0.5 the scaleSize will be 0.5. This method is definitly better in using, specially when using the scaleSize binding with a slider.
This add cssStyle attributes in CPCompatibility.j as well.
Previously the behavior of the methods convertRect/convertPoint didn't work like Cocoa, specially when the two views weren't in the same Window. Now it does.

Test app in Tests/Manual/ScalingTest