[QLab] Updated video status

[Christopher Ashworth]

Hi all,

I found the cause of John's crash, and it was indeed a threading  
problem.  So please do consider the current beta version of the Video  
Cue unreliable.

As much as I wanted that last beta to be the final one, of course I'm  
not going to make it official until it proves itself stable.

I want to go over it all again with a rested eye to make sure I  
didn't miss anything, but I hope to give everyone another beta to try  
tomorrow.

-C