some admin pages had a container within a container

see #244

management/templates/mail-guide.html

 <style>#panel_mail-guide table.table { width: auto; margin-left: .5em; }</style>
 
-<div class="container">
+<div>
 	<h2 style="margin-bottom: 0">Checking and Sending Mail</h2>
 
 	<div class="row">

management/templates/sync-guide.html

-<div class="container">
+<div>
 	<h2>Contacts &amp; Calendar Synchronization</h2>
 
 	<p>This box can hold your contacts and calendar, just like it holds your email.</p>