GetSampleInfo
Also add full xmldoc
We want to access this property for computing lifetime
This ensures the spinner's hit judgement will always be centre instead of in the top left corner.
BeatmapDifficulty
IBeatmapDifficultyInfo
Resolves #2133.
The underlying spin counting doesn't match stabnle, so they have been near impossible to complete until now.
# Conflicts: # osu.Game.Rulesets.Mania/UI/Column.cs