Raw types warnings removed.

Raw types replaced. Added a asSubClass method in LayoutInflater which
will (correctly) throw a ClassCastException when the inflated class is
not a View subclass.

Reduced the number of warnings in GenericInflater, but those remaining
are valid. A lot of unsafe class casts happen between parent (P) and
item (T) types that will generate runtime errors if the XML is not valid.

Change-Id: I887fd67769a51ab54c6092e1270dbe3bfb6313ca