Fix slider velocities
This will be usable from the editor moving forward also - where every hit object can have its own velocity multiplier on top of the control point one.
Taiko fixes
Taiko drawable generation
Conflicts: osu.Desktop.VisualTests/Tests/TestCaseTaikoHitObjects.cs osu.Desktop.VisualTests/Tests/TestCaseTaikoPlayfield.cs osu.Game.Modes.Taiko/UI/TaikoHitRenderer.cs osu.Game.Modes.Taiko/osu.Game.Modes.Taiko.csproj
Taiko drumroll drawing