Refactoring index, and fixing python "se3ToXYZQuat"

Fix bug in prismatic joint + add planar joint + add translational joint

[Major][Python] Fixing function se3ToXYZQUAT. Change method display in robot_wrapper according to this fix

Fixing inclusion of Lua and urdfdom whereas they were not found

Add LUA parser

Fix bug in spherical joint and add missing algorithm exposition 

[cmake] Add install for libpinocchio.so

[Major][Unittest] Unifying unittest framework with boost_test_suite

Aggregating pull request of Thomas to handle fixed joint when parsing urdf file

    dimension of q is still minimal
    inertias are merged with the closest the movable parent
    placements of fixed join are recorded in model to send it to gepetto-viewer
    COM and RNEA have been tested locally - unit-test to come.

Add attributes in model.hpp
	- names of fixed body
	- indexes of their closer movable parent
	- visuals booleans
	- number of fixed body
modify display method in robot_wrapper
	- compute and send the absolute placement from relative to the closer movable parent