Fix commands problem

[glannuzel]

When sending goal_position, it may happen some commands are not taken into account (not correctly updated on server side):
Doing:

for joint in reachy.joints.values():
        joint.goal_position = 0

sometimes r_wrist.roll or r_shoulder.roll are not correctly updated (only joints to be sent in a first message, all other joints are sent in a second message)

The problem is increased doing:

for joint in reachy.joints.values():
        joint.goal_position = 0
        time.sleep(0.01)

where each joint is sent in a single message, all orbita2d axis1 and orbita3d roll and pitch can sometimes be overwritten by an older goal_position.