Add nifty button icons.

guacamole/src/main/webapp/styles/ui.css

@@ -515,7 +515,7 @@ div.section {
 
 #connection-add-form,
 #user-add-form {
-    margin: 0.5em;
+    margin-bottom: 0.5em;
 }
 
 body:not(.manage-connections) .require-manage-connections,
@@ -604,4 +604,16 @@ div#logout-panel {
 .list-pager-buttons {
     text-align: center;
     margin: 1em;
-}
+}
+
+button#logout {
+
+    background-image: url('../images/action-icons/guac-logout.png');
+    background-repeat: no-repeat;
+    background-size: 1em;
+    background-position: 0.5em 0.45em;
+
+    padding-left: 1.8em;
+
+}
+