Some quick markup/design fixes

Move top margin from breadcrumbs to main content panel. This makes sure
content is always pushed away from the top. Also adds more debug info
and some styles to make it look nicer.
Add video playback!

Woohoo, everything works! So far... This modifies the link handler
to be far more readable, because comma-delimited strings suck. It
also adds the basic video player along with some video stats.

Would be nice to hack the player a bit too, so need to see what's
possible with the Player APIs at some point.