-Hide all visual properties of features when they are part of a body
-Propagate all body visual changes to features
-Separate display mode from body mode to enable setting display mode for both "tip" and "through" modes
-Use default visuals for body shape and only make "through" a new display mask mode for the children
- Moved all common code for part design features view providers to a base
class.
- Move shared code for Sketch based features to newly created
ViewProviderSketchBased class
- Add ViewProviderSketchBased to initialization
- Make Pad and Pocket ViewProviders to use the shared code
- Minor fixes to TaskFeatureParameters and some derived classes
