[galaxy-commits] commit/galaxy-central: jgoecks: First pass on composite tracks. To facilitate composite tracks, draw_helper now returns jQuery Deferred objects rather than null when drawing cannot occur so that tile drawing can be more closely tracked. Current limitations of composite tracks: (a) can be created only inside groups; (b) only tracks of the same type can be composited; and (c) no normalization is done b/t tracks. Also implemented generic save/restore functionality. Pack JS scripts.