Allow freeze on stop

[gaetancollaud]

This PR allow to freeze the image when we call stop(). This is really useful for RTSP because we cannot pause. The only way to pause is to call stop() and play() again with a new url with the good timestamp but the image is gone while we paused.

There is no compatibility issue, we can still use stop as it is and the image will not be frozen (same as current behavior).

If you want to froze the image when stopping the stream you have to do it like this:

stop({
    freezeImage: true
});

[gaetancollaud]

I just went across the issues to see if someone had the same one. I found #183 which I wrote in 2006...

[gaetancollaud]

dead PR I'm closing it