Added Scrimba intro

Updated home page to include the Scrimba screencast that Per Harald Borgen made as an introduction to mini.css.

docs/index.html

@@ -133,7 +133,8 @@
       <div class="row">
         <div class="col-sm-12 col-lg-10 col-lg-offset-1">
           <h2>Quick overview</h2>
-					<p>Take a couple of minutes to explore what makes <strong>mini.css</strong> different from all those other CSS frameworks and UI toolkits.</p><br/>
+					<p>Take a couple of minutes to explore what makes <strong>mini.css</strong> different from all those other CSS frameworks and UI toolkits.</p>
+					<figure style="margin: 0;"><div style="position: relative; padding: 0.5rem; padding-bottom: 42%; margin-bottom: 0.25rem;"><iframe style="display: none; border: 0; position: absolute; width: 100%; height: 100%;" onload="this.style.display='block';" src="https://scrimba.com/cast/cast-1949.embed"></iframe></div><figcaption style="padding: 0.5rem;">Intro to mini.css by <a href="https://scrimba.com/casts/cast-1949" style="font-size: 0.8125rem; text-decoration: none;">Per Harald Borgen</a></figcaption></figure><br/>
 					<h3>Why should I use mini.css?</h3>
 					<p><strong>mini.css</strong> is a lot lighter than a lot of other full-featured CSS frameworks (e.g. Bootstrap, Semantic UI), but it is not a micro framework (e.g. Milligram, Pure.CSS). Instead, <strong>mini.css</strong> blurs the line between full-featured and micro frameworks by providing lots of modules and components in a very small file. All the things you expect to find in a CSS framework, such as grids, styling for common elements and typography, along with some more complex components such as tabs or cards are all present in <strong>mini.css</strong>.</p>
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