DATAMONGO-1072 - Fix annotated query placeholders not replaced correctly.

We now also check field names for potential placeholder matches to ensure those are registered for binding parameters.

Original pull request: #233.
DATAMONGO-1050 - Explicitly annotated Field should not be considered Id.

We changed the id resolution to skip properties having an explicit name set via @Field unless they are marked with @Id. This means that

@Field(“id”) String id;

will be stored as “id” within mongodb. Prior to this change the fieldname would have been changed to “_id”.
Added tests to ensure proper field mapping for various "id" field variants.

Original pull request: #225.
DATAMONGO-1077 - Fix Update removing $ operator for DBRef.

Prepare issue branch.
DATAMONGO-1077 - Fix Update removing $ operator for DBRef.

We now retain the positional parameter when mapping field names for associations.