Fix bug where JSLint indicator was always gray. StatusBar's init was a bit
intertangled with its main client (previously EditorManager, now
EditorStatusBar), which meant other clients can't guarantee the status bar
is initialized before their own htmlReady() handler merely by require()ing
StatusBar. Fixed by having StatusBar initialize itself. This makes it a bit
less generic... but only a bit - it was already not reusable since it's all
singleton APIs and its HTML contains hardcoded support for EditorStatusBar's
UI.

Minor other fixes: log console errors when StatusBar APIs are called too
early (instead of silently dropping on floor); fix copyright date; remove
unneeded JSLint globals.