Implement extension importer.

Assets/Cryville/Crtr/Extensions/ExtensionImporter.cs

@@ -0,0 +1,18 @@
+using Cryville.Crtr.Extension;
+using System.IO;
+
+namespace Cryville.Crtr.Extensions {
+	internal class ExtensionImporter : ResourceConverter {
+		static readonly string[] SUPPORTED_FORMATS = { ".dll" };
+		public override string[] GetSupportedFormats() {
+			return SUPPORTED_FORMATS;
+		}
+
+		public override void Convert(FileInfo file, ConversionSession ses) {
+			ses.AddResource(new ExtensionResource(file.Name, file));
+		}
+	}
+	public class ExtensionResource : FileResource {
+		public ExtensionResource(string name, FileInfo master) : base(name, master) { }
+	}
+}