Cleanup: remove outdated in-person events from header menu

Previously these in-person events (conferences, etc) for the `blog.jquery.com` header menu were produced dynamically by some PHP code shared by various header menus; however that functionality has been removed[1].

For consistency with `jquery.com`, remove the list of events; the ones removed here appear to be from Y2014 or so, so they're fairly out-of-date.

Resolves #13.

[1] - jquery/jquery-wp-content@88519ab

Author: jayaddison

jquery/header.php

@@ -69,11 +69,6 @@
 					</li>
 					<li class="dropdown"><a href="http://events.jquery.org/">Events</a>
 						<ul class="wide">
-							<li><a href="http://appendto.com/what-we-do/training/schedule/jquery-virtual-training-april-2014/">Apr 16-17 | jQuery Virtual Training</a></li>
-							<li><a href="http://jqueryuk.com/?utm_source=jqueryorg&utm_medium=banner&utm_campaign=jqueryorgbanner">May 16 | jQuery UK</a></li>
-							<li><a href="http://appendto.com/what-we-do/training/schedule/jquery-virtual-training-june-2014/">Jun 17-19 | jQuery Virtual Training</a></li>
-							<li><a href="http://events.jquery.org/2014/chicago/">Sep 12-13 | jQuery Chicago</a></li>
-							<li><a href="http://2014.cssdevconf.com/">Oct 13-15 | CSS Dev Conf 2014</a></li>
 						</ul>
 					</li>
 					<li class="dropdown"><a href="https://jquery.org/support/">Support</a>