Small Breaking Change for Dialog code

I've just committed some MvvmCross Touch and Android dialog code which will cause a small breaking change for existing implementations.


The main breaking change is that the `Bind` extension methods have moved from the individual Dialog projects to a shared location:

Cirrious.MvvmCross.Binding.BindingContext

If you use Dialog, then you will soon need to change your code to include a using for this namespace.


Beyond that, I've also included some excellent AutoView updates from @csteeg and I've committed some additional changes which:

• unify the DateTime Element behaviour across both platforms
• includes a default binding target name of Value for all ValueElements
• includes Expression based binding for all Elements.

You can see this new Expression based binding in:





To compare this to the previous code, see the diff in the revision history: https://gist.github.com/slodge/5706116/revisions - the old code will still work, but the new Expression based code may be easier to use because of its intellisense and refactoring support.