Implement extension importer.

Assets/Cryville/Crtr/Extensions/Umg/Extension.cs

@@ -1,18 +0,0 @@
-using Cryville.Crtr.Extension;
-using System.Collections.Generic;
-
-namespace Cryville.Crtr.Extensions.Umg {
-	public class Extension : ExtensionInterface {
-		public override IEnumerable<ResourceConverter> GetResourceConverters() {
-			return new ResourceConverter[] {
-				new ChartResourceImporter(),
-				new RulesetResourceImporter(),
-				new SkinResourceImporter(),
-			};
-		}
-
-		public override IEnumerable<LocalResourceFinder> GetResourceFinders() {
-			return null;
-		}
-	}
-}

Assets/Cryville/Crtr/Extensions/Umg/Extension.cs.meta

@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: 323b670cbdea58644ac9ba20fc4c1a89
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: