Add sound offset for ruleset config.

Assets/Cryville/Crtr/ChartPlayer.cs

@@ -368,6 +368,7 @@ namespace Cryville.Crtr {
 				});
 			}
 			sv = _rscfg.generic.ScrollVelocity;
+			soundOffset += _rscfg.generic.SoundOffset;
 
 			FileInfo skinFile = new FileInfo(
 				string.Format("{0}/skins/{1}/{2}/.umgs", Game.GameDataPath, rulesetFile.Directory.Name, _rscfg.generic.Skin)

Assets/Cryville/Crtr/Config/RulesetConfig.cs

@@ -12,6 +12,12 @@ namespace Cryville.Crtr.Config {
 			[JsonProperty("skin")]
 			public string Skin { get; set; }
 
+			[Category("gameplay")]
+			[JsonProperty("sound_offset")]
+			[Step(0.04f)]
+			[Precision(1e-3)]
+			public float SoundOffset { get; set; }
+
 			[Category("deprecated")][Obsolete]
 			[JsonProperty("scroll_velocity")][DefaultValue(1)]
 			[LogarithmicScale][Step(0.5f)][Precision(1e-1)]
@@ -19,6 +25,7 @@ namespace Cryville.Crtr.Config {
 
 			public Generic() {
 				Skin = "";
+				SoundOffset = 0;
 				ScrollVelocity = 1;
 			}
 		}