Add debug output on configuration validity
New method in solver to try creating a direct path between init and goal configurations. Call for a roadmap reset if a collision obstacle is loaded
New steering method implementation : first lines
Homogeneize coding style.

  - TypeWkPtr -> TypeWkPtr_t.
Add accessors for maxIterations and errorThreshold

  in classes ConfigProjector and ProblemSolver.
Add a local map of numerical constraints in ProblemSolver

  - numerical constraints are stored by name in a local map in order to be
    inserted into the ConfigProjector.
Merge branch 'master' of https://github.com/florent-lamiraux/hpp-core
Move tryDirectPath method to pathPlanner
Fixing potential-method, do not compile yet
Start debug potential-method.hh
Change PotentialMethod algo to gradient
Merge branch 'master' of https://github.com/humanoid-path-planner/hpp-core
Merge branch 'master' of https://github.com/florent-lamiraux/hpp-core

Conflicts:
	src/problem-solver.cc
Allow WeighedDistance computation for anchors
Fix compilation bugs except 'const'
Use ChildrenIterator loop to optimize WeighedDistance computation
Merge branch 'master' of https://github.com/humanoid-path-planner/hpp-core
Add install commands for PotentialMethod and start adding debug outputs
Fix errors, works without obstacle and optimization
Move finishSolve() from DiffusingPlanner to PathPlanner, and add debug outputs