How to add assets to a Joomla template

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$doc = JFactory::getDocument();

$doc->addStyleSheet('templates/' . $this->template . '/css/screen.css','text/css','screen');

$doc->addCustomTag('<meta name="author" content="Matt Thomas, matt@betweenbrain.com" />');

$doc->addFavicon('templates/' . $this->template . '/favicon.png','image/png','shortcut icon');

$doc->addScript('https://raw.github.com/LeaVerou/prefixfree/master/prefixfree.min.js');

$doc->addStyleSheet('http://fonts.googleapis.com/css?family=ubuntu');

$doc->addStyleDeclaration('  body {font-family: "Ubuntu", serif;}');

$doc->addCustomTag('<!--[if lt IE 9]>');
$doc->addCustomTag('<script src="//html5shim.googlecode.com/svn/trunk/html5.js"></script>');
$doc->addCustomTag('<![endif]-->');