DATAMONGO-777 - Upgraded to Mongo Java Driver 2.11.3.

Upgraded to latest mongo Java Driver release to benefit from new API introduced (required to fix DATAMONGO-534). Adapted test cases to API changes in DuplicateKey.
DATAMONGO-534 - GridFsTemplate supports queries with sorting.

Upgraded to Mongo Java Driver 2.11.3 to be able to forward the sorting options contained in a Query to eventually be able to return sorted results when querying for files.
DATAMONGO-752 - Improved keyword detection in QueryMapper.

The check for keywords in QueryMapper now selectively decides between checks for a nested keyword (DBObject) object and the check for a simple key. This allows the usage of criteria values starting with $ (e.g. { 'myvalue' : '$334' }) without the value being considered a keyword and thus erroneously triggering a potential conversion of the value.

Moved more logic for a keyword into the Keyword value object.