Fail to create ROS message from stored Mongo document

[cburbridge]

The MessageStore proxy can't recreate ROS messages when they include a list of ROS types. For example, trying to store a geometry_msgs/Polygon fails because it containts a list of Point32:

geometry_msgs/Polygon tabletop
  geometry_msgs/Point32[] points
    float32 x
    float32 y
    float32 z

The message is stored ok in the database, but when recreated the points list is created as a list of python dictionaries not a list of ROS messages.

The problem is in util.py, line 150, only dicitionaries are expanded into the message. We need something like:

 elif isinstance(value, list):
            lst=[]
            for i in value:
                msg = tp_of_msg()
                fill_message(msg, i)
                lst.append(msg)
            setattr(message, slot, lst)    

finding the type of the message that should be in the list could be done by looking at the _slot_types field of the message class, but then primitive types - eg. list of ints - would need special attention....

[hawesie]

If this is high priority, could you put that code in? Else I can do it once the navigation/scheduler is completed.