[bin/morse] Fix argparse use with python 3.3.x

Python silently breaks the default semantic of argparse with subparsers
between python 3.2 and python 3.3 (see http://bugs.python.org/issue16308).

Add some workaround to 'restore' the expected semantic for both version.
Rename morse_inspector.py to morse_inspector for consistency reason
[cmake] Always link python module to lib python

It is needed to please several linker, in particular OSX one
[ros] Initialization properly the D parameter of camera_info

D parameter of camera_info must be initialized to zero to denote
uncalibrated camera
[builder] log information about uncaught exceptions
[doc] add multi-node rewrite in RELEASE_NOTES
[datastream] Register socket server in a smarter way.

Allow running multiples morse instance on the same computer in
particular. Fix #433.
[datastream] Ignore 'not connected' exception when shutting down socket

From  muratsevim. Fix #432
[doc] Added a CITATION file

Based on this suggestion:
http://blog.rtwilson.com/encouraging-citation-of-software-introducing-citation-files/
[doc] sync RELEASE_NOTES and What's new
[camera] create new scene for each camera

fix #371
[builder] add basics after creating scenes
[builder] name new scenes
[builder] add comment camera-scene in env.create
[camera] update objects' pose/orientation

on the scene. introduce a new wierd stuff :-)
[camera] add scene as underlay (not shown)
[test] update video_camera pgm images
[camera] set viewport to camera
[builder] do not create scene for external robot