Updating docs banners

docsite/_themes/srtd/layout.html

@@ -200,8 +200,8 @@
 <a href="http://www.ansible.com/tower?utm_source=docs">
 <img src="http://www.ansible.com/hubfs/Docs_Ads/TowerDocs.png">
 </a>
-<a href="https://www.eventbrite.com/e/ansiblefest-nyc-2015-tickets-16058031003">
-<img src="http://www.ansible.com/hubfs/Docs_Ads/Untitled_design_1.png">
+<a href="http://www.ansible.com/ansible-book?utm_source=docs">
+<img src="http://www.ansible.com/hubfs/Docs_Ads/Get_2_full_chapters_of_Ansible-_Up_.png">
 </a>
 <br/>&nbsp;<br/>
 <br/>&nbsp;<br/>