The Library button, the view's header (search box or playlist name) and
the seek row now share one band under the transport boxes, instead of the
seek row hanging alone with a header strip below it. The now-playing panel
caps at 560px and the gaps between controls share the rest evenly; more
room under the menu bar. Long playlist names shrink up to 2pt, then elide.
The boxed controls were centered on the whole bar while the now-playing
panel hung from its top, so the bpm box sat ~11px below the panel beside
it. The panel is now CONTROL_HEIGHT tall and every control shares its top
edge; the seek row hangs under the panel.
trav