Fix missing scrollbar when version diff table is too wide for screen

at least, this seems to fix.  not sure if/why we shouldn't apply this style
globally always, but playing it safe for now

tailbone/templates/master/view_version.mako

@@ -3,6 +3,17 @@
 
 <%def name="title()">changes @ ver ${transaction.id}</%def>
 
+<%def name="extra_styles()">
+  ${parent.extra_styles()}
+  <style type="text/css">
+
+    .this-page-content {
+        overflow: auto;
+    }
+
+  </style>
+</%def>
+
 <%def name="page_content()">
 ## TODO: this was basically copied from Revel diff template..need to abstract