[ticket/10699] Long h2 title breaks div.minitabs in MCP

Fixed overlapping of Subject title over the minitabs.
Added css property to cp.css under MCP Specific tweaks.
Wrapped h2 and #minitabs under .tabs-container with
clear: both

PHPBB3-10699

phpBB/styles/prosilver/template/mcp_topic.html

@@ -1,5 +1,5 @@
 <!-- INCLUDE mcp_header.html -->
-
+<div class="tabs-container">
 <h2><a href="{U_VIEW_TOPIC}">{L_TOPIC}: {TOPIC_TITLE}</a></h2>
 
 <script type="text/javascript">
@@ -35,7 +35,7 @@ onload_functions.push('subPanels()');
 		</li>
 	</ul>
 </div>
-
+</div>
 <form id="mcp" method="post" action="{S_MCP_ACTION}">
 
 <div class="panel">