Add documentation about BBB videoconference to install guide

documentation/installation_guide.html

@@ -66,6 +66,7 @@
   <li><a href="#12._Setting_cron_up">Setting chronological tasks</a></li>
   <li><a href="#13._Changing_language_name_order">Changing the language's firstname/lastname order</a></li>
   <li><a href="#14._Improving_files_download">Improving files download time</a></li>
+  <li><a href="#15._Videoconference">Videoconference</a></li>
 </ol>
 
 <br />
@@ -884,6 +885,22 @@ $_configuration['enable_x_sendfile_headers'] = true;
 If you have issues with files taking a long time to download, make sure you reconfigure your webserver and add this line. You should see an notable difference in download time.
 </p>
 <hr style="width: 100%; height: 2px;" />
+<h2><a name="15._Videoconference"></a>Videoconference</h2>
+<p>
+  Chamilo supports the connection to two different videoconference servers: BigBlueButton and OpenMeetings.<br />
+  While BigBlueButton seem easier to install, more clearly documented and more
+  esthetically finished, some users have manifested that OpenMeetings
+  consumes less bandwidth, is less restrictive in terms of running environments
+  and offers more tools and connectors.<br />
+  The decision is up to you, but in any case you will have to install a
+  videoconference server separately from the normal Chamilo LMS installation
+  process.<br />
+  You will find the <a href="http://docs.bigbluebutton.org/install/install.html">installation guide for BigBlueButton here</a>. Once installed,
+  issue a "bbb-conf --secret" on the command line to get the parameters to
+  indicate in the "Videoconference" plugin in Chamilo (platform settings page).<br />
+  This should make an additional "Videoconference" tool icon appear in every course.<br />
+</p>
+<hr style="width: 100%; height: 2px;" />
 <p>
   <br />
   <br />