Force value changed and invalidate implementation in property adapter.

Assets/Cryville/Crtr/Config/IPropertyAdapter.cs

@@ -14,6 +14,7 @@ namespace Cryville.Crtr.Config {
 		object GetValue();
 		void SetValue(object value);
 		event Action ValueChanged;
+		void Invalidate();
 		object MapValue(object value);
 		bool SetMapped { get; }
 		object MapValueInverse(object value);
@@ -38,7 +39,10 @@ namespace Cryville.Crtr.Config {
 		public object GetValue() { return _prop.GetValue(_target, null); }
 		public void SetValue(object value) { _prop.SetValue(_target, value, null); }
 
-		public event Action ValueChanged { add { } remove { } }
+		public event Action ValueChanged;
+		public void Invalidate() {
+			ValueChanged?.Invoke();
+		}
 
 		readonly double _precision;
 		readonly double _step;