Simplify IntervalList implementation enough to work for its usages
Simplify IntervalList implementation enough to work for its usages

peppy/osu-new,peppy/osu,ppy/osu,NeoAdonis/osu,smoogipoo/osu,ppy/osu,NeoAdonis/osu,smoogipooo/osu,UselessToucan/osu,peppy/osu,peppy/osu,ppy/osu,UselessToucan/osu,UselessToucan/osu,smoogipoo/osu,smoogipoo/osu,NeoAdonis/osu