change add_mex to add_executable for ik c++ test
fix the problem of seg fault by changing add_mex to add_library in drakeQuatUtil. Also add robotnum in URDFRigidBodyManipulator
1. find some bugs in RigidBodyConstraint.cpp and inverseKinBackend.cpp
2. Add test for RigidBodyConstraint when time is not in the tspan
Forgot to delete an unused library
cleaner directory ref
set cMakelists the way I think they should be.  working on cmake