Add a "retry" option to keep video playing when error detected.

I think the error handling is important feature. After removing it, the video stopped at the place where error was detected, and I have to move my mouse to the Play/Pause button to continue it. It's a little boring for me.
I know other people may encounter problems by this error handling. But I think we can create an option to let user decide whether to use this feature.
Tested on 0.5.9