This reverts commit a6d8b28221.
a6d8b28221
ScoreMultiplier not currently working - that's a more involved change that requires the aforementioned "BeatmapAttributes" changes.
Also restructures with the addition of a ManiaBeatmap which holds definitions for "groups" of columns. At the moment these are empty save for a "Column" property, but can be expanded in the future, maybe.
Fixes the recent AppVeyor errors
Fixes up deserializing.