Use abstract base class instead of interfaces for Binding objects.

Bug 19627511
Bug 19709604

Changed generated classes to end with "Binding" instead of "Binder"
to avoid confusion with Android Binders.

Removed DataBinder class and moved the important aspects of its
contents to ViewDataBinding.

Improved mapping of Views in included layouts. Avoid traversing
included layouts while looking for bound expressions.

Change-Id: I1f28093b0792d5428d07192f1fc458a5b4b788b2