[pr2] Updates to PR2 blender model

- Adjusted torso armature to have correct '0'
- Reparented torso_lift children to torso_armature

This would previously prevent the head and arms to move along with the torso.
It actually looks like a bug in the BGE (or at least, an inconsistency).

This change also required clearing the parent inverse matrix of head and arms, and
updating accordingly transformations of these parts. This have introduce small
inaccuracies in bodies placement compared to original URDF.
[armatures] Fix misplaced 'armature.update'

This would prevent prismatic joints to actually move
[armatures] Correctly read prismatic joint value + minor refactoring

We assume the joint elongation is always on Y (ie, channel.pose_head[1]). Need to be checked
with other prismatic joints, though.

Unit-test robots/pr2/torso-sockets.py now pass.
[examples] delete outdated armature_samples

and references in doc
[examples] update rosace example
[examples] deleted outdated pr2/hri scenarii
[builder] pr2: do not super(self.__class__, self)
[profile] add block /10
[human] default classpath
[examples] update ros example multi

``del env`` to create MORSE configuration.