little css fix for admin system

[Juraj Variny]

Hi,

when using admin system on tables with many columns, rightmost columns are cropped by browser due to rigid tundra layout. This fixes it, by enabling table scrolling:

--- a/devtools/templates/turbogears/+package+/public/css/admin.css
+++ b/devtools/templates/turbogears/+package+/public/css/admin.css
@@ -19,6 +19,9 @@ a.edit_link{
 }
 
 /* admin list view */
+.crud_table {
+    overflow : auto;
+}
 .crud_table .grid {
     border-collapse: collapse;
     border: 1px solid #ccc;