Certain members of ItemAutomationPeer should be public

[batzen]

Certain members of ItemAutomationPeer should be public to enable people to write better code by avoiding code copies or usage of reflection.
The members in ItemAutomationPeer especially affect custom automation peers for ItemsControl like controls.
Those internal members are, for example, used in RibbonGroupDataAutomationPeer.

Members that should be public:

• GetWrapper
• GetWrapperPeer

Exposing those members would remove the need to use reflection to call those methods, as their code can't be easily copied as GetWrapper relies on the internal type IGeneratorHost.