Multiple (3) fingers grip and manipulation demo

1. Using spring constraint of Springhead as virtual coupling.
2. Physics step runs at haptic rate (1kHz).
3. Number of fingers is set at FingerGrip.cpp.

How to clone this repo

1. Clone this repositry at xxx/???/HapticInteraction/Haptic_TwoFingerGrip
2. Springhead2 should put on xxx/Springhead