fixed issues on mongodb operators+default template func for controller_base

I fixed some bugs encountered in the use of mongodb operators : 
  * [l.125@module/mongodb_data_storage/mongodb_data_storage.php] While operator is populated, func access results using index "0" ( $values[0] ) but mongodb collection returns indexed array of arrays ( ex: docs[_id] [doc] ) and iterator_to_array is not reindexing array by default.
  * [l.109@module/operator/operator.php] Mongodb collection returns array but operators::set_values needs an object.
  * [l.102@module/operator/operator.php] operators::get was issuing notices when property was not set.

I added a new functionality in controller_base that try to fallback to a default template if it was not defined previously by controller.