Use quaternion for rotations in hpp::Configuration.
Update documentation.
Add getObstaclePosition method and changing type of corbaserver rotation from matrix to quaternion

Conflicts:

	idl/hpp/corbaserver/common.idl
	src/tools.cc
Fix convertion between hpp::Configuration and flc::Transform3f.
Fix method Problem::lockDof

  - return 0 on success and -1 on failure,
  - catch exceptions.
Add a method to load obstacles from an urdf file.
Cosmetic change: make comment more explicit.
Fix method Obstacle::loadObstacleModel.