Added lua exporting

Editor/LuaImporter.cs

@@ -0,0 +1,17 @@
+using UnityEngine;
+using System.IO;
+using UnityEditor.AssetImporters;
+
+namespace SplashEdit.EditorCode
+{
+    [ScriptedImporter(1, "lua")]
+    class LuaImporter : ScriptedImporter
+    {
+        public override void OnImportAsset(AssetImportContext ctx)
+        {
+            var asset = new TextAsset(File.ReadAllText(ctx.assetPath));
+            ctx.AddObjectToAsset("Text", asset);
+            ctx.SetMainObject(asset);
+        }
+    }
+}