title: MvvmCross detecting RequestClose or back button pressed
body: <p>I found this topic which says that MvvmCross has no way of detecting RequestClose or use pressing a back button: <a href="https://stackoverflow.com/questions/10515990/wp7-mvvmcross-detect-requestclose-or-">WP7 MVVMCross Detect RequestClose or BackKeyPressed inside ViewModels</a>
  backkeypressed-inside-viewmodels</p>
  
  <p>Did anything change since May, 2012? Any reasons why this functionality isn't build into MvvmCross? I don't want to re-engineer the wheel it seems like this can be built very simply into Android, WP7, and iOS. If I don't find solution, I will end up building it.</p>