This commit fixes collision detection using class Problem.

  - use clearConfigValidations instead.

  Constructors that used to take const Problem& as input now take
  const ProblemConstPtr_t.
  Classes that used to store a const Problem& now store a
  ProblemConstWkPtr_t.

  - Add "NoValidation" as a key for PathValidations selection.

  This new method tries to connect the initial and goal configurations to
  other connected components of the roadmap before developing the roadmap
  further. When planning from an initial to goal configurations without
  precomputed roadmap, this method should be equivalent to tryDirectPath.

  - numberNonLockedDofs is deprecated.