Simple "staticstuff" plugin for writing unit tests on plugin static asset linking.

Simple "staticstuff" plugin for writing unit tests on plugin static asset linking.

It doesn't do much... it just has a static directory with a "bunnify"
CSS file and has a unit test that returns a json encoded set of a
staticdirect with both this plugin enabled and also
with (theoretically) a file distributed with MediaGoblin (it isn't
really, but in our case that doesn't matter.)

Also set up the static_setup hook / PluginStatic object for this
plugin; testing that with `./bin/gmg theme assetlink` seemed to work.
(And argh, need to update that command name, I know.)

This commit sponsored by Bradley Kuhn.  Thanks bkuhn!