Derive from XmlSerializer
adjust references, persistence update
Add some files regarding "PropertyGrid" copied from Monodevelop.
Add an empty property widget show its own properties

Add also missing bitmaps copied again from monodevelop.
Redo some persistence updates previously reverted by some refacturing.
Move some folders to clarify parts from monodevelop
Move some folders to clarify parts from monodevelop
Property grid enable help bar
Merge branch 'master' into