Fixed null pointer exception on KinectRuntimeNode.cs and added KinectDept...

...hPointCloudNode

The KinectDepthPointCloudNode receives a KinectRuntime input, and
outputs XYZ coordinates for the data read in from the depth stream.  A
resolution pin allows for all pixels in the stream to be considered, on
a division of the full amount of pixels by the factor specified in the
resolution pin.

The null pointer exception ocured when attempting to close vvvv while a Kinect (Microsoft) node was inside the patch.