Added a custom script importer for lua files

Creates text assets out of lua file contents

Assets/Fungus/Scripts/Editor/LuaScriptedImporter.cs

@@ -0,0 +1,14 @@
+using UnityEngine;
+using UnityEditor.Experimental.AssetImporters;
+using System.IO;
+
+[ScriptedImporter(1, "lua")]
+public class LuaScriptedImporter : ScriptedImporter
+{
+    public override void OnImportAsset(AssetImportContext ctx)
+    {
+        TextAsset lua = new TextAsset(File.ReadAllText(ctx.assetPath));
+        ctx.AddObjectToAsset("main", lua);
+        ctx.SetMainObject(lua);
+    }
+}