Add documentation for iOS web applications

Add several options to improve iOS web apps with meta tags when
adding a web page to the Home Screen.

Closes #1352.
Update to Normalize.css 1.1.2
Update to jQuery 1.10.0
Update to jQuery 1.10.1
Update to Google Universal Analytics

This is an optimized version of the official Google Universal Analytics snippet,
based on http://mathiasbynens.be/notes/async-analytics-snippet.
The only difference is that this version still uses
`document.getElementsByTagName('script')[0]` instead of `document.scripts[0]`
for Firefox < 9 support.

Unminified, optimized code:

    (function(window, document, script, variableName, scriptElement, firstScript) {
      window['GoogleAnalyticsObject'] = variableName;
      window[variableName] || (window[variableName] = function() {
        (window[variableName].q = window[variableName].q || []).push(arguments)
      });
      window[variableName].l = +new Date;
      scriptElement = document.createElement(script);
      firstScript = document.getElementsByTagName(script)[0];
      scriptElement.src = '//www.google-analytics.com/analytics.js';
      firstScript.parentNode.insertBefore(scriptElement, firstScript)
    }(window, document, 'script', 'ga'));

    ga('create', 'UA-XXXX-Y');
    ga('send', 'pageview');

Minified:

    (function(b,o,i,l,e,r){b.GoogleAnalyticsObject=l;b[l]||(b[l]=function(){(b[l].q=b[l].q||[]).push(arguments)});b[l].l=+new Date;e=o.createElement(i);r=o.getElementsByTagName(i)[0];e.src='//www.google-analytics.com/analytics.js';r.parentNode.insertBefore(e,r)}(window,document,'script','ga'));ga('create','UA-XXXX-Y');ga('send','pageview');

Closes #1347 and #1369.
Docs: update information about `print styles`

Fix: h5bp/html5-boilerplate#1386
Remove Google Frame message

As said at http://blog.chromium.org/2013/06/retiring-chrome-frame.html Google Frame was retired/obsolete.

Changed "chromeframe" class to "browsehappy"
Add vertical centering for audio-, canvas- and video-tags

Remove the gap between videos, audio and canvas and the bottom of
their containers by vertically centering the tags.

Closes #1326.
Remove Chrome Frame meta tag and HTTP header hints

See also `Retiring Chrome Frame - developer FAQ`:
https://developers.google.com/chrome/chrome-frame/

Close #1396.
Add `initial-scale=1` to meta viewport

iOS 6 fixes the infamous orientation change bug, so a better experience
is provided by reintroducing `initial-scale=1`.
Updating jQuery to 1.10.2.