update readme with exmaple and dev commands

Readme.md

@@ -5,3 +5,28 @@ This is a POC oscilloscope emulator with [live demo](http://m1el.github.io/wosco
 Full explanation available on [the blag](http://m1el.github.io/woscope-how/)
 
 Code is available under MIT license.
+
+### Example
+```html
+<audio id="myAudio" controls src="woscope-music/khrang.mp3"></audio><br>
+<canvas id="myCanvas" width="800" height="800"></canvas>
+<script src="dist/woscope.js"></script>
+<script>
+    var myCanvas = document.getElementById('myCanvas'),
+        myAudio = document.getElementById('myAudio');
+
+    woscope({
+        canvas: myCanvas,
+        audio: myAudio,
+        callback: function () { htmlAudio.play(); }
+    });
+</script>
+```
+
+### Dev commands
+```sh
+npm install      # install dev dependencies
+npm run demo     # run demo locally with livereload
+npm run build    # build dist files
+npm run lint     # check source files with jshint
+```