Added Relative MetaTaskDyn, modified task-dyn-limits.cpp and created secondOrderKinematics option for SolverKine

Relative MetaTaskDyn working. CMakeLists modified.
Added gain utilisation and some useful comments to task-dyn-limits.cpp.
Little and not significant change in task-dyn-pd.cpp (just deleted an unuseful space).

Option SecondOrderKinematics for SolverKine created. Deleted unuseful signal velocityOUT.
Little and not significant change in solver-op-space.cpp (some commentaries and changed variable name from "qdot" to "dq")