Web guidelines font spec should include both beta and release font names

[Mark Shuttleworth]

When we release the Ubuntu font into the public arena, we will keep iterating it with new features and glyphs. So we will alwyas have both a next-generation beta font, and the current released font, available. So our web sites should use:

body {
  font-family: UbuntuBeta, Ubuntu, 'Bitstream Vera Sans’, ‘DejaVu Sans’, Tahoma, sans-serif;
}

The default CSS for Canonical and Ubuntu sites should use that to ensure that font beta-testers are always seeing the beta font in action, but everyone else still sees the released font.