Add width directive to meta viewport tag

Add "width=device-width" to meta viewport tag via aurora_preprocess_html().

function aurora_preprocess_html(&$vars) {
  // Viewport!
  $viewport = array(
    '#tag' => 'meta',
    '#attributes' => array(
      'name' => 'viewport',
      'content' => 'width=device-width, initial-scale=1.0',
    ),
  );