- Reduce matrix sets to two types
- add method for the initialization of matrices
- add methods for the computation of scalar products
- add global objective types
- call by reference and const correctness

the objective

- Add method updateObjective
- Add method updateLSObjTerm
- Add 2 addTerm methods

Add new accessors

Add overloaded accessor functions

LinearInvertedPendulum2D
intermediate-qp-matrices

- add type standard_ls_form_t
- add type invariant_objective_part_t
- add type variant_objective_part_t
- add method getTermMatrices

- Add generator-vel-ref.cpp/hh
- Add mpc-trajectory-generation.cpp/hh

- Add intermediate-qp-matrices.hh/cpp

-Add method solve(int solver) to problem-vel-ref
-Rename problem-vel-ref to qp-problem and ProblemVelRef_s to QPProblem_s

Set now to 1e-6. We probably should not go above.

This non-atomic commit (which is bad) fix the following problems:
- Improve the stopping phase.
- Remove useless m_Q
- Remove useless BuildingConstantPartOfTheObjectiveFunctionQLD
and useless BuildingConstantPartOfTheObjectiveFunctionQLDANDLQ
- Rename Problem_s in ProblemVelRef_s

The scheme changed because the height of the CoM is not 0.814
from Kajita's book, but the real CoM height computed for the robot.
It changes slightly the numerical result.

O2 with -DNDEBUG is faster than O3 and previous flags
on a Xeon 3.2 GHz with 2Mb of L2 cache.

The flags needs further investigation.