Multiple fixes:

1. Entities can have both long and Long as field type (same for int, double, float).
2. Null GeoPt and Date fields are ignored instead of throwing exception.
3. Polymorphic types are handled using @DocumentIndexSubClass annotation (added test for same).
4. Updated app-engine version to be 1.9.5 and java compiler to 1.7 (this should probably be left for cnosumer to decide).

@marcosvidolin Apologies for formatting changes. Let me know if there is a standard formatter you're using or I can provide mine.