Switched to an alternate method of rendering quality and notes.

Now notes are rendered as boxes colored according to the piece's quality.
This is the first step towards merging quality with notes.
Brightened up the quality colors, since they're now used as backgrounds.
Disabled HTML rendering for the note boxes.
Changed quality to be per note instead of per piece.
Renamed a few things for terseness.

* PieceQuality -> Quality;
* PieceNote -> Note;
* (In Note) quality -> pieceQuality. Okay, that one's actually longer,
  but it's more representative.