Add initial-scale=1 to the viewport meta

Ref: h5bp/html5-boilerplate#1398.

src/index.html

@@ -4,7 +4,7 @@
         <meta charset="utf-8">
         <title>HTML5 Boilerplate: The web's most popular front-end template</title>
         <meta name="description" content="HTML5 Boilerplate is a professional front-end template for building fast, robust, and adaptable web apps or sites. Spend more time developing and less time reinventing the wheel.">
-        <meta name="viewport" content="width=device-width">
+        <meta name="viewport" content="width=device-width, initial-scale=1">
         <link rel="stylesheet" href="http://fonts.googleapis.com/css?family=Open+Sans:400,700">
         <link rel="stylesheet" href="css/main.css">
         <script src="js/html5.js"></script>