Store track's file size upon first play
Track maintains its progress as it plays

Track.prototype.timeRemaining() returns the number of seconds
left, based on how much data has been read out of the file's total
size.

Pipes data through a transform stream which updates the Track's
_progress property. Unfortunately audio is about 2s behind the
file read stream, so timeRemaining() will appear to end early.
More or less live updating of time remaining

Jukebox emits a heartbeat every second while playing, which is
picked up by the view.
Merge branch 'master' into progress

Conflicts:
	src/view.js
Differentiate pausing and stopping a track

(Stopping resets the track progress entirely)
When paused, track can restart where it left off
Apply correction to timeRemaining()
Don't need to assign that pipe to a property
Auto-end jukebox heartbeat on a callback
Track resets its progress when ending.

Noted that sometimes the track's progress gets stuck at a non-zero
value when a track ends on its own. This fixes that, renaming the
_stop callback to _close to not conflict with the method that
joins stop() and pause().
checking off yet another todo
Merge branch 'progress'
live progress bumps version to 0.3.0