A better solution for media file/template info overlays

Since the JS-based solution does not work well for cases where the
overlay is larger than the (very small) image, we'll have to go
with a CSS-based solution. This sets the height of the overlay
to at least 7em, which should cover the core info of the overlay
(which is usually 4 lines of text). Also, we'll have to go with
overflow: scroll; in case the info is longer.

Not a good solution in a reponsive context, but it should work. :(

References #230

templates/2k11/admin/serendipity_editor.js.tpl

@@ -765,12 +765,6 @@
                     updateOnResize: true
                 });
             }
-            // Also sync height of info overlays
-            $('.equal_heights').each(function() {
-                var $el = $(this);
-                var containerHeight = $el.css('min-height');
-                $el.children('.media_file_preview, .template_preview').css('minHeight', containerHeight);
-            });
         }
     }