Adds Introduction page

Simplified Introdction page

Spiced up home page more, style changes to code examples

_includes/home-banner.html

@@ -1,4 +1,4 @@
-<header class="home--banner">
+<header class="home-banner">
   <h1>Liquid</h1>
   <p>Safe, customer facing template language for flexible web apps.</p>
   <p class="btn-row">

_includes/home-users-grid.html

@@ -0,0 +1,24 @@
+<div class="home-users-grid">
+  <div class="home-users-grid__item">
+    <a href="http://jekyllrb.com/" target="_blank">
+      <img src="/images/jekyll-logo.png" />
+    </a>
+  </div>
+  <div class="home-users-grid__item">
+    <a href="http://www.desk.com/" target="_blank">
+      <img src="/images/salesforcedesk-logo.png" />
+    </a>
+  </div>
+  <div class="home-users-grid__item">
+    <a href="https://www.zendesk.com/ " target="_blank">
+      <img src="/images/zendesk-logo.png" />
+    </a>
+  </div>
+  <div class="home-users-grid__item">
+    <a href="http://500px.com/" target="_blank">
+      <img src="/images/500px-logo.png" />
+    </a>
+  </div>
+</div>
+
+<p class="home-users-blurb">...and <a href="https://github.com/Shopify/liquid/wiki#who-uses-liquid" target="_blank">many more!</a></p>