MQTT client for Robot API

[anacleto85]

Define the python client for exposing Robot API through MQTT

[anacleto85]

The Python components instantiating handler threads and configuring subscriptions to MQTT topics specified in the xml file under the resource folder have been published.

@marcvinci @sebastianstock,

Under the folder 'mobipick', you might find the Python class extending the general abstract handler. The class implements the handler method responsible for mapping predicates (with parameters) of dispatched timeline tokens to robot actions/commands.

The extended class inherits methods for publishing back to the planner execution feedback (success, failure, interrupt) - See the methods publish_{success, failure, interrupt} in the code of the abstract class BridgeHandler

[marcvinci]

@anacleto85
I commited an example usage of the mobipick_api here.

It is just very simple calls and how to use it with comments, there still needs to be a matching between the predicate and predicate parameters received from the mqtt request.

Make sure the simulation is running and that the mqtt client runs somewhere, where the ros catkin workspace is sourced, so probably inside the docker.