appengine/search: add more detailed test cases.

Change-Id: If6c017f87b390460e373abb77f04623bf7788018
appengine/search: add GeoPoint

Change-Id: I27393599bb58ea3196dbdfb581bae8ea3edb884b
appengine/search: Add FieldLoadSaver, analogous to datastore.PropertyLoadSaver.

Change-Id: Id18065467b8e61a0db461b62b097fa0738cc7bab
Update README to document APIs that have been deprecated or removed.

Change-Id: If5c0b76a4801607fb8cd976bb3ef5229135d25d4