Updated ranger_monitor to latest pyranger/pyrobots changes

Works now as expected
Fixed again computations of positions relative to beacons

While here, display cartesians positions in rnager_monitor
Updated API for eyes

To take full advantage of being now able to independently set each eyes/lids
Fixed bug when setting robot speed
Use int as ID for beacons

While here, ranger.res.ID is now an enum
Fixed another bug when setting robot speed
[action/nav] Improved  turn

It should now be more accurate
Use threading.Event to notify state updates

Fixed accordingly 'get_full_state'.

While here, the initial pose of the robot is initialized
from what the charging station sees (if the charging station
is in sight)