_s: Adhere to updated WordPress core code formatting.

* Update PHPDoc.
* Add periods to the end of comment sentences.
* Limit line length to 80 chars.
* Use C++-style PHP comments only for function and file documentation.
_s: Remove `image.php` and related code. Image attachments will be
displayed by `single.php`. See
http://codex.wordpress.org/Template_Hierarchy
Merge pull request #339 from obenland/image.php

Remove `image.php` and related code.
Apply a natural box layout model to all elements; see #341.
Add braces around single-line conditionals. See http://make.wordpress.org/core/2013/11/13/proposed-coding-standards-change-always-require-braces/.
Improve Post Format Archive heads. Follows up on #95 and https://github.com/Automattic/_s/commit/e3b4907946696c324877b775bdfea8314af1799a#diff-ff638db82c6ac72a05781ba3e086fdf0L48.
Fixed typo in inline comments.
Merge pull request #347 from taupecat/upstream

_s: Fix spelling in inline comments.
Removed bullet that referenced keyboard-image-navigation.js, since that file was deleted.
Merge pull request #349 from taupecat/upstream

_s: Remove reference to keyboard-image-navigation.js. That file doesn't exist anymore.
_s: Use verbose syntax for conditionals in templates.
Merge pull request #343 from Automattic/add-braces

_s: Add braces around single-line conditionals.
_s: Update wpcom compat file to wrap contents in a hooked callback.
_s: Split navigation template tag in context-specific tags.
List for main-navigation

Hey guys, I am proposing to remove li in front of the current_page_item and current-menu-item. It's slightly more efficient without and of course all works the same :)
Merge pull request #351 from emiluzelac/patch-7

List for main-navigation
Make date formats translatable

Following up on a similar change to 2014, make the date formats for monthly and yearly archives translatable.
Merge pull request #352 from sabreuse/patch-1

_s: Make date formats translatable.
_s: Add closing brackets to avoid fatal error. Props @gatespace for
intial patch. Fixes #355.
Fixed Issue #354: Removed link on line 90 that was going to a page that no longer exists.