app-display: Slight cleanup and style update

Being no longer an independent menu pane, both the toggle() and
close() functions are no longer needed, and the view's structure
can be simplified a bit.

Also update the style to fit into the view selector.

https://bugzilla.gnome.org/show_bug.cgi?id=634948

data/theme/gnome-shell.css

@@ -508,10 +508,7 @@ StTooltip StLabel {
 }
 
 .all-app {
-    border-radius: 10px;
-    background-color: #111111;
-    border: 2px solid #868686;
-    color: #ffffff;
+    padding: 10px;
 }
 
 .app-section-divider-container {
@@ -524,16 +521,6 @@ StTooltip StLabel {
     background-image: url("separator-white.png");
 }
 
-.all-app-controls-panel {
-    height: 30px;
-}
-
-.all-app-scroll-view {
-    padding-right: 10px;
-    padding-left: 10px;
-    padding-bottom: 10px;
-}
-
 #dash > .app-well-app {
     padding: 6px 12px;
 }