Implement dynamic computation of connected components.
Assert that connected component has at least one node.
Allow to create new configurations as close as desired from an existing node.
Mode displayConfig function to hpp-model.
Fix operator<< for classes Node and Roadmap

  - move operator inside namespaces,
  - operator<< calls method print defined in the classes.
Do not add edges to roadmap while going through the list of connected components

  - adding edges may imply connected component merging and thus modification
    of the list of connected components.
  - store edges to insert in the roadmap and insert them after the loop.
Suppress multi-line comment warning
DifferentiableFunction are parametric
Constraints are now parametric
Update .gitignore and cmake submodule
Change from LeafParameter to level set parameter
Add member isParametric_ to LockedDof
Add step by step planning to ProblemSolver class
Check if a path exists in ProblemSolver::finishSolveStepByStep
Make solver methods virtual in class ProblemSolver
Add protected method to set the problem and the roadmap.
Make Problem::checkProblem virtual
Fix bug about LockedDof on JointSO3
Add method virtual ProblemSolver::initializeProblem
Add method ProblemSolver::resetRoadmap