Synchronize cmake submodule.
Reset problem when robot is loaded, not when calling ProblemSolver::solve

  Formerly, until calling method solve, additional obstacles where not taken
  into account.
Cosmetic changes

  - re-indent files before inserting directed roadmap,
  - delete trailing white spaces.
Make possible to use no path optimizer.
Move test of existence of a path from PathPlanner to Roadmap.
Implement oriented roadmap

  - new implementation of connected components.
Move graph-connected-component.hh to src.

  User do not need this class.
Rename CCGraph -> ConnectedComponentGraph.
Simplify insertion at end of list.
Add methods to simplify management of connected component,

  - when creating a new node and connecting it both ways to another node, the
    new node is simply added to the connected component of the previously
    existing one.
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.
Add steering method based on potential fields, fix PathVector iteration number