FastRandom
LegacyRandom
osu.Game
BaseDifficulty
Beatmap<T>
BeatmapDifficulty
IBeatmapDifficultyInfo
PatternGenerator.isValid
MathF-functions are faster than the Math-counterpart and it looks cleaner, so use MathF when we cast to float or int anyway.
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.