New fix proposal for the CPU hitting 100% even when no kinect is connected.

The commit https://github.com/wieden-kennedy/Cinder-KCB2/commit/349bcc2d193c2b9061afaf8723f79afe1a6eb289 didn't completely fix the issue https://github.com/wieden-kennedy/Cinder-KCB2/issues/8
KCB2 is still cranking up my CPU to 100%, even when Kinect isn't connected. 

Proposal to improve the fix, going to sleep also in the case where the application has not connected an event handler.