books.jquery.com: Remove unused theme

Introduced in 2012 with commmit d90583e, but to the best
of my knowledge the site existed.

There were briefly DNS entries for a staging site at
http://stage.books.jquery.com, but Archive.org has no captures from
either it nor http://books.jquery.com.

Author: Krinkle

INSTALL.md

@@ -48,7 +48,7 @@ Check `httpd.conf` to ensure that the PHP module is enabled as well.
 You do not need to configure your `/etc/hosts` file for `local.*` because `jquery.com`'s DNS handles this for you. However, if you plan to work offline, you can use the following rules:
 
 ```
-127.0.0.1 local.jquery.com local.api.jquery.com local.blog.jquery.com local.books.jquery.com local.releases.jquery.com local.learn.jquery.com local.plugins.jquery.com
+127.0.0.1 local.jquery.com local.api.jquery.com local.blog.jquery.com local.releases.jquery.com local.learn.jquery.com local.plugins.jquery.com
 127.0.0.1 local.jqueryui.com local.api.jqueryui.com local.blog.jqueryui.com
 127.0.0.1 local.jquerymobile.com local.api.jquerymobile.com local.blog.jquerymobile.com
 127.0.0.1 local.jquery.org local.brand.jquery.org local.contribute.jquery.org local.events.jquery.org local.meetings.jquery.org

README.md

@@ -60,7 +60,7 @@ Complete the installation process by pointing your browser at http://vagrant.jqu
 You do not need to configure your `/etc/hosts` file for `vagrant.*` because `jquery.com`'s DNS handles this for you. However, if you plan to work offline, you can use the following rules:
 
 ```
-172.27.72.27 vagrant.jquery.com vagrant.api.jquery.com vagrant.blog.jquery.com vagrant.books.jquery.com vagrant.releases.jquery.com vagrant.learn.jquery.com vagrant.plugins.jquery.com
+172.27.72.27 vagrant.jquery.com vagrant.api.jquery.com vagrant.blog.jquery.com vagrant.releases.jquery.com vagrant.learn.jquery.com vagrant.plugins.jquery.com
 172.27.72.27 vagrant.jqueryui.com vagrant.api.jqueryui.com vagrant.blog.jqueryui.com
 172.27.72.27 vagrant.jquerymobile.com vagrant.api.jquerymobile.com vagrant.blog.jquerymobile.com
 172.27.72.27 vagrant.jquery.org vagrant.brand.jquery.org vagrant.contribute.jquery.org vagrant.events.jquery.org agrant.meetings.jquery.org

sites.php

@@ -170,15 +170,7 @@ function jquery_sites() {
 			),
 		),
 		# Historical: Database blog_id 14 is reserved for api.qunitjs.com.
-		'books.jquery.com' => array(
-			'blog_id' => 15,
-			'cookie_domain' => '.jquery.com',
-			'body_class' => 'jquery',
-			'options' => array(
-				'blogname' => 'jQuery Books',
-				'stylesheet' => 'books.jquery.com',
-			),
-		),
+		# Historical: Database blog_id 15 is reserved for books.jquery.com
 		'events.jquery.org' => array(
 			'blog_id' => 16,
 			'cookie_domain' => '.jquery.org',