Update JS generation commands

Its ugly. It should not be in the README.md. But it works and it fix the problem.

js/README.md

@@ -3,9 +3,16 @@ mq_js_bundle.js contains most common macroquad's dependencies JS code in one JS
 `mq_js_bundle.js` was made by:
 
 ```bash
+#!/bin/bash
+
+function wrap_js {
+    echo "(function () {" >> mq_js_bundle.js
+    cat $1 >> mq_js_bundle.js
+    echo "}());" >> mq_js_bundle.js
+}
 cat ../../miniquad/js/gl.js > mq_js_bundle.js
-cat ../../quad-snd/js/audio.js >> mq_js_bundle.js
-cat ../../sapp-jsutils/js/sapp_jsutils.js >> mq_js_bundle.js
-cat ../../quad-net/js/quad-net.js >> mq_js_bundle.js
-minify mq_js_bundle.js
+wrap_js ../../quad-snd/js/audio.js
+wrap_js ../../sapp-jsutils/js/sapp_jsutils.js
+wrap_js ../../quad-net/js/quad-net.js 
+minify mq_js_bundle.js > mq_js_bundle2.js
 ```