Hypercast browser extension v0.0.8

In some cases video playback would flicker back and forth between
multiple positions when seeking, especially with a large number of
clients connected. This has been made much less likely by implementing
a slightly modified synchronization algorithm.

Detection of the active video element is faster now in most cases. If
there is only one choice, then it is selected immediately. Only if
there is more than one candidate and Hypercast cannot disambiguate do
you have to hit play on the main content to show it which is which.