[20160914] Success to Stand Up

(Valkyrie sustains its balance for 4 min. Even after 8 min, it does not diverge)

Finally, Valkyrie stands up with reaction force control and does not fall down for a long time (> 8min). I believe that we finally find a way to make it stable. 

Previously, WBOSC based CoM control with contact constraint does not provide stable balance motion.

Let me write down the equation I used to generate torque command.