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

To do so, added a new parameter ( placementOffSet) which enables to propagate the length of a fixed body to child joints  and edit the urdf tree to remove bypass fixed link when encountered and handled.

The fixed links are not displayed in the viewer yet and not saved in model yet

Aggregating pull request of O.Stasse in order to add Travis

Necessary to avoid travis time out trigger.

Follow the advice of gcc by casting directly with the proposed
CoeffBasedProduct template.
Makes gcc happy.
This patch was initially proposed by Florent Valenza but
with another type.

There is still an issue on ConstraintXd.
This commit *does not* compile is here for book-keeping.