Merge branch 'develop'
Version 0.4.0: Merge branch 'develop'

Conflicts:
	manifest.json
slider has pointer cursor only when song is playing
dragging works, but a little buggy on click
dragging is much better, still offset issues
report error code instead of broken message
Merge branch 'draggable' into develop
Simplify gMusic interfacing
State transitions, better background loading, general cleanup
time text should update with drag
Better selectors
simplify music_status
switch to single-quotes
fix music_status
fix current time on drag lol
fix button interfacing
Move js to bottom of popup
infobar is hidden when no song is playing, also minor robustness (imfl)
bump version to 0.4.1
Merge branch 'release-0.4.1'