* Implement exp3, exp6, log3, and log6 functions by copying
    implementation from explog.py.
  * Add same documentation as in explog.py.

[Major][C++] Added Joint limits to joint model and to Pinocchio Data. Also added an algorithm to compute joint limits. Based on the model of the limits, it computes and store the actual limits in Data. We then have access to the values in Data in python binding. The algorithm is here in future cases where the limits will not only be static but dependent of the configuration

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

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

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.