Fix ViewFactory initializer and caching issues
removed  ViewFactory.CreatePage(Type type) as it was unnecessarily forcing the initialiser Action<TViewModel, Page> to always be the base class ViewModel
Allow cached page to be updated by initializer (coders can provide their own logic down the line to keep the page content static)
throw exception when viewmodel cannot resolve (educational)
Fix ViewFactory initializer and caching issues - indentation. what else?
Merge pull request #85 from mrbrl/xamarin_master

Fix ViewFactory initializer and caching issues