Thanks to M. Morisawa for notifying.

This was witnessed in TestHerdt.

- Introduce solution_t Solution_
- Move Previews to soluton_t 
- QPProblem::dump_problem -> QPProblem::dump
- introduce solution_t.reset() and solution_t()
- smaller changes

"Four shalt thou not count, neither count thou two,

excepting that thou then proceed to three. Five is right out."

Bug noticed by M. Morisawa.

Please check if this patch corrects or destroys the realization of others PGs.

- Documentation, Attribute names

TODO to complete this : Center the CoM at the end of a movement

- Document set_support_state

- Remove unfinished object door
- Some warnings (not all of them)

Also realize a little rewriting, to simplify the code.

With initial position, velocity, acceleration.

(one useful commit...)

The compilation and link informations should now be gathered in a .pc file

Note : LSSOL sources are not included

- Minor bugfix
- Add method dump_problem(Time)
- Minor changes to improve robustness