Add "startNow" parameter to locomotionControl

- add new parameter "startNow" to allow starting the controller as soon
as the module starts.
- initialize desired positions of COM, swinging foot and joint posture
to the read values, so that the controller starts always with sensitive
references
- fix bug in computation of COM forward kinematics using 2d array
(rather than 7d)
Just a comment
Add parameter "startIn" to locomotionPlanner

Launching the module with the option "--startIn 21" the module will
start with a delay of 21 seconds