Fixed body timestamp conflict with default.

@bantherewind I'm pretty sure the issue I was experiencing was caused by a timestamp problem now. For instance, body tracking would only work if I set the framerate to <30fps.

For some reason, the new frame bodies would be tracked and added to the list but not copied over to device's mFrame. Essentially, this condition would fail: https://github.com/wieden-kennedy/Cinder-KCB2/blob/dev/src/Kinect2.cpp#L1148

In other words, the frame on which bodies are updated would have the same default timestamp as mFrame, and so the inner loop (body update) would never be reached.

As a solution, I placed the default timestamp within the for-loop.

_I'm wondering if the timestamp logic could be removed. What about updating mFrame's components within each KCBIsFrameReady condition?_