Revert "Add LeapMotion SDK support"

This reverts commit 291c446c28fbe772b161cdb0246e1ebfef83ca84.
Revert "Revert "Add LeapMotion SDK support""

This reverts commit 8ce145085b3783782fafd051becbb0e339d5dfa1.
Support for LeapMotion and worklist 19734

-  Introduce the DeviceTracker class  to abstract all the possible
devices
- Introduce the MotionTracker ( a DeviceTracker ) that contains a
transform tree of joints
- Add Leapmotion class as a MotionTracker and the support for the
Leapmotion sdk in external
- Add InputController as the abstraction of a MotionTracker/Joint for
Javascript