Remove executable permissions on content-single.php

By default content-single.php was executable by all users, which doesn't seem intended.
Merge pull request #226 from jeremyfelt/master

Remove executable flag from content-single.php
Rework menu navigation: these changes build off pull request #239 for issue #200
 * Only set button and menu if container is not null.
 * Break up the "return early" conditional into multiple parts.
 * Shorten the name of the toggled class from `toggled-on` to `toggled`.
 * Restore the "Hide menu toggle button if menu is empty." documentation.
 * Remove the `nav-menu` class. The previous code would replace any custom custom classes applied via `wp_nav_menu()` or template file.
 * Replace the `nav-menu` selector is style.css with selectors that will target both a custom nav menu and a page menu. These changes could use critical feedback. Do you know of an edge case where they might not work as expected?
Rework Navigation Menu Part 2
 * Separate scoping and assignment so that a decision does not need to be made as to whether we should intermix spaces and tabs on the left
 * Restore the previously removed nav-menu class addition to the first unordered list in `#site-navigation`.
 * Restore the `.navigation-main.toggled-on .nav-menu` selector.
 * Remove rules for the `.main-small-navigation ul` selector.
Merge pull request #242 from mfields/navigation-menu

Rework Navigation Menu. Closes #200, #205, #237, #243.
Update README.md

Change the reference to DocBlock search to actually display a space (to make it more consistent with the second appearance, after the OR).
_s: Add custom taxonomy support for term descriptions in taxonomy
archives.

We don't even have to check for a context before printing the
description, `term_description()` does all the heavy lifting for us.

Props @jasondpx. Fixes #128.
_s: Include "entry updated" as part of the hAtom. Props @michiecat. See
#131, fixes #170.
_s: Don't show separator between meta data. Fixes #72.
_s: Remove back compat for custom header/background. Fixes #244.
Simplified archive titles

The current archive titles are verbose and fusty. This commit
simplifies them to the bare minimum needed (and wanted by actual users)
for description, orientation, and navigation.
Merge pull request #246 from ianstewart/cleaner-archives

Simplified archive titles: The current archive titles are verbose and fusty. This commit simplifies them to the bare minimum needed (and wanted by users) for description, orientation, and navigation.
_s: Update search form markup to make it forward compatible with HTML5
search form in 3.6. As a result, `searchfornm.php` can be safely
removed in the future. Also fixes #240.
Merge pull request #245 from asdfgh746/patch-1

Update README.md to make it look like the concrete example.
Extra single-quote in "Search"

A trailing singe-quote has found its way into the search button value,
resulting in the button displaying "Search'" instead of "Search".
Merge pull request #248 from soulseekah/master

_s: Remove trailing single-quote in search button.
_s: Simplifies the attached image template tag by only querying for ids.