Access joint by name in Robot::setJointBounds and Problem::lockDof.
Homogeneize data-structures

  Replace nameSeq by Names_t.
Add accessors for maxIterations and errorThreshold.
Add an interface method to set numerical constraints in ConfigProjector

  - Problem::setNumericalConstraints.
Cosmetic changes

  - fix documentation main page.
Put code into try catch block when running corba request.
error message correction
Cosmetic change: fix comment.
Add an interface method to get a joint transformation.
Add a python class for quaternions.
Fix some compilation warning.
Update to new prototype of hpp::core::LockedDof::create.