Also removing a lot of mania code relating to gravity mod for now.
This exposes LifetimeOffset from DrawableHitObject which is used by the XSRG rulesets to adjust the life time range by the VisibleTimeRange.
Update SpeedAdjustmentCollection.cs
This was here to support dynamic re-ordering of hit objects and speed adjustment containers, however there needs to be more work done to TimingControlPoints/MultiplierControlPoints in general before this is possible.
# Conflicts: # osu-framework