Initial Leap Support (Orbit Camera One Hand Mode)

# Setup of Infrastructure
Initial integration of the LeapSDK:
- Reference to the LeapCSharp.NET4.0.dll wrapper
- PostbuildScript to copy the necessary other dlls (Leap.dll, LeapCSharp.dll) (currently x86 builds)

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Direct calls from the LeapListener to the active CameraController are not the best solution but sufficent for the moment.

## Orbit One Hand Camera Mode Description
Move the hand in x direction to rotate the model around the upward axis,
pitch and roll of the hand control the corresponding angle of the model