Fix embedded objects not populated on queries.

OGM-557

The new unit test shows the problem with @Embedded objects not being populated by a query (not find).
There was a lot of similar code between MassIndexingMongoDBTupleSnapshot.java and MongoDBTupleSnapshot.java that I refactored.
Interestingly, the test still passes for me when doing so. Which error/failure do you exactly get?