[Major] Now handle prismatic joint when parsing urdf. Only cartesion X,Y or Z are accepted, unaligned axis bring crash

[Major] Correction of bugs in JointRevoluteUnaligned and its unittest. The urdf parser nows takes into account this joint. Added a new enum in cartesian axis

[Python][Major] Integrated modifications in Gepetto viewer that reference a window by id instead of string

[Python][Major] Corrected wrapper to CRBA to have  symmetric M, added missing types to access data wrapper, added operator in motion.

[Python] Added xyzquatToSe3 and modified rpyToSO3 to accept matrix instead of tupple as input (impact is marginal, but the modif was necessary to properly parse Maximilien input data).

Conflicts:
	src/multibody/model.hpp
	src/multibody/parser/urdf.hpp

[Minor] Correct initialization of Vector3 & added method to compute spatial motion quantity translated in a frame by a translation quantity

Conflicts:
	todo.txt

Conflicts:
	todo.txt

[Debug] Correct bug in Symmectric test that was preventing tests to compile (at least on ubutun 14.04 LTS)

[partial cherry-pick from a1b1bc29d7 and 153e8322b1a3].

Python: Modifies robot wrapper to adpat it to gepetto viewer, moved the code specific to romeo in a new dedicated romeo wrapper module, add the installation on the new file in CMake.
[Partial cherry pick from 1aefa7f6,7feba3,36b5d7,b87a2b53 and 153e832]