Crush images, save some bytes
Crush beast images down.
Remove ?mdn cache-buster on tabzilla.js

We were using this temporarily as we waited for some important updates
to hit the Tabzilla CDN. This has since happened, making the
cache-buster unnecessary.
Merge pull request #1789 from darkwing/png-crush

Crush images, save some bytes
Merge pull request #1790 from darkwing/slim-beasts

Crush beast images down.
Merge pull request #1791 from openjck/tabzilla-no-cache-busting

Remove ?mdn cache-buster on tabzilla.js