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/style.css

@@ -2259,7 +2259,8 @@ label .perm_name,
     box-sizing: border-box;
     color: #fcfcfc;
     height: 100%;
-    overflow: hidden;
+    min-height: 7em;
+    overflow: scroll;
     padding: .5em 1em;
     position: absolute;
     top: 0;