add yawLock.py to implement a lock process with fixed foot assumption
add yawLock.py to implement a lock process with fixed foot assumption

patmarion/director,mitdrc/director,empireryan/director,empireryan/director,RussTedrake/director,manuelli/director,mithrandir123/director,rdeits/director,openhumanoids/director,RussTedrake/director,RussTedrake/director,openhumanoids/director,patmarion/director,RobotLocomotion/director,rdeits/director,rdeits/director,gizatt/director,mitdrc/director,manuelli/director,openhumanoids/director,openhumanoids/director,manuelli/director,mitdrc/director,gizatt/director,mitdrc/director,gizatt/director,edowson/director,rdeits/director,edowson/director,edowson/director,RobotLocomotion/director,RobotLocomotion/director,edowson/director,edowson/director,patmarion/director,manuelli/director,mithrandir123/director,mithrandir123/director,manuelli/director,mithrandir123/director,empireryan/director,patmarion/director,empireryan/director,patmarion/director,empireryan/director,RussTedrake/director,gizatt/director,RobotLocomotion/director,mitdrc/director,gizatt/director,rdeits/director,RussTedrake/director,RobotLocomotion/director,openhumanoids/director,mithrandir123/director