Currently videojs player defaults to the lowest resolution, usually 160p ogg. This is pretty ugly and not what we want unless we're on a really slow mobile phone.

Instead should use some logic to pick the initial source:

• format/codec preferences: vp9 > vp8 > theora
• resolution preferences: pick biggest that fits in the available area by default
  • possibly use ogv.js-specific hack to bump down resolution if slow
  • switch when going fullscreen ?