Breaks BandpassFilter into a separate file.
Makes scoring less broken.

Scoring should actually work now. That is, it should produce a number
at the "end" of the game. Fixes a bug in playlist `clipStartedAt`
calculation that wasn't taking the clip offset into account. Fixes
logic for various playlist status booleans.
Adds vu meters to SVG asset source.
Adds animated VU meters.