Add resource action. Implement play chart and import resource action.

Assets/Cryville/Crtr/Browsing/Actions/ResourceAction.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace Cryville.Crtr.Browsing.Actions {
+	public abstract class ResourceAction<T> : IResourceAction<T> {
+		public abstract string Name { get; }
+		public abstract int Priority { get; }
+		public abstract void Invoke(Uri uri, T resource);
+		public void Invoke(Uri uri, object resource) {
+			if (resource == null) throw new ArgumentNullException("resource");
+			if (!(resource is T)) throw new ArgumentException("Mismatched resource type.");
+			Invoke(uri, (T)resource);
+		}
+	}
+}