Add KDL library to check its inverse kinematics solver
SkeletonFitting, encapsulated all fitting methods in fit_skeleton_cloud.

This leads to code simplification in SkeletonController
Added class IKSolver.

This will simplify SkeletonFitting and encapsulate the method use to solve
the inverse kinematics problem.
IKSolver works with one bone on origin
IKSolver know works with chains of any length.

Also it saves the previous position to produce smooth transformations.
Moved Extras.cpp and .h code to BVHFormat.

Is code was poluting the global namespace with some global variables and
causing the KDL library compile errors.
IKSolver now works with bones that are not in the origin.

In SkeletonController the final position is transformed to the appropiate
coordinate system. Added some code to try and add an segment that does this
to get a simpler code, still a wip.
IKSolver added method start_chain with matrix offset.

Addind a extra segment still does not work, using result translation instead.
IKSolver now uses LMA inverse solver.
SkeletonController, added solver success check, deleted previous IKAN code
IKSolver, manually check result to fix some errors.

The iksolver would return sometimes a fail flag when it actually found the
solution.
SkeletonController, changed ik_chain to start with root node.

Insertion is less eficient but code in much more clear.
IKSolver changed argument position in solve_chain
IKSolver fix error with solving with one bone.

New LMA solver fails with one bone and some other times, if it fails
then try with nr solver
IKSolver,simplified solve_chain code.

Now it is divided in two methods solve_chain_1_segment and
solve_chain_several_segments, it is faster and code gets simpler.
Skeletoncontroller fix inverse kinematics with one bone.

With one bone inverse kinematics failed, so added code to use the
result nevertheless
SkeletonFitting fit_head_and_back now uses IKSolver.

Also deleted methods move_goal and get_rand_0_01 and their class variables
SkeletonFitting delete solve_2_bones methods.

Since they have been replaced by the IKSolver methods
skeletonFitting, fit_legs now uses IKSolver also.

Deleted get_swivel_angle method since it was used for IKAN only
DELETED all remaining IKAN code from the project.