timeline.tt, busybird.css: spinner is now placed at the right of navbar.
Add t/lib/BusyBird/Test/StatusHTML.pm. t/WebAPI_html.t is rewrited with that module.
t/lib/BusyBird/Test/HTTP: add parse_html() class method. This is necessary because HTML::TreeBuilder does lots of meddling stuff by default, which is harmful for testing (but useful for parsing nasty HTML texts). Test::StatusHTML now uses parse_html() method.
t/Status.t: add tests for rendering status IDs.