Close drawer on back

Clover/app/src/main/java/org/floens/chan/ui/controller/RootNavigationController.java

@@ -110,6 +110,16 @@ public class RootNavigationController extends NavigationController implements Pi
         drawerLayout.openDrawer(drawer);
     }
 
+    @Override
+    public boolean onBack() {
+        if (drawerLayout.isDrawerOpen(drawer)) {
+            drawerLayout.closeDrawer(drawer);
+            return true;
+        } else {
+            return super.onBack();
+        }
+    }
+
     @Override
     protected void controllerPushed(Controller controller) {
         super.controllerPushed(controller);