Load comments template only when comments are open or there's at least one comment

To be consistent with single.php and to ensure that an empty div (<div
id="comments" class="comments-area">) isn't outputted when both
comments are closed and there aren't any comments.
On hashchange, make sure we set focus for elements that need it. Essentially the same as 136, but without jquery
Search form improvements:

- Add "searchform" class to form element, easier styling
- Better gettext for label, placeholder, and submit text, easier for translators
- Remove "name" attribute from submit button, not needed and it adds cruft to URL

See also http://core.trac.wordpress.org/ticket/15081
_s: Adhere to WordPress CSS class naming conventions. See
http://make.wordpress.org/core/handbook/coding-standards/css/#selectors
for details.
Merge branch 'master' of https://github.com/Automattic/_s.git
_s: Simplify and unify navigation classes throughout Underscores.

For more information about the philosophy behind the new approach,
see http://24ways.org/2012/a-harder-working-class/
_s: Move role declaration to the end of the element for consistency.
Remove _s_content_nav( 'nav-above' ); from the top of all templates. Fixes #148
Merge pull request #139 from aaronjorbin/master

make "Skip to content" link work in browsers that are doing_it_wrong, but without jQuery. props @aaronjorbin
Let us try this one more time. Revert all changes made to _s up until commit debefa merge until #131 has had a proper code review.
Manually revert all changes made after debefa8b98d so that the code proposed in #131 gets a proper review.
Update style.css
Update style.css
Merge pull request #132 from davidensinger/master

Load comments template only when comments are open or there's at least one comment in image.php and page.php
Fix indentation on comments block
Fix spacing and tabbing problems in page.php introduced in 413403827878875d1fd3505e442a0448d77120ff and 054aa194a7d86ee090836aad946aac04cc0e7fc8
_s: Simpler selector for lists within lists.
_s: Aggregate translation strings and make comment edit links easier to
style.
_s: Enable live preview for Header Text Color in Customizer. Change also
removes an !important declaration in Custom Header CSS rules.
_s: Formatting changes:

- Reduce element comments to either the element id or the first element
class.
- Tabs > Spaces.
- Improve adherence to formatting guidelines.