Throttle FrameGrabber/OwnFlowHandler: it provides too many frames and overwhelms OwnFlow

[shadow1runner]

Multiple Options:

• Try to connect the signal/slot using a BlockingConnection - this forces the FrameGrabberThread to wait until the actual frame is consumed. This, however, also implies that any intermediate frames are not consumed from the capturing device (unless OpenCv buffers them?) - worth a try
• Implement throttling according to current fps by connecting the already emitted OwnFlow/timingStatistics event
• Hack: Simply skip every e.g. 9 of 10 frames

All of the aforementioned options influence the KF quite heavily - so investigations are necessary how heavy.

The alternative option: Move quad very slow :S