themes lib MDL-24895 Multiple fixes to better handle overflow.

Major tasks undertaken in this patch:
* New format_text argument, overflowdiv.
* New page layout Report.
* Review of all format_text calls.
* Added support for the report layout to all themes.
* Changed forum post display from tables to divs.

mod/wiki/renderer.php

@@ -67,6 +67,7 @@ class mod_wiki_renderer extends plugin_renderer_base {
             $table->colclasses = array('wikisearchresults');
             $html .= html_writer::table($table);
         }
+        $html = html_writer::tag('div', $html, array('class'=>'no-overflow'));
         return $this->output->container($html);
     }