Clients: Fix memleak issues in various clients of weston

In many clients of weston, Display was not being destroyed so added it.
Also destroy windows, widgets which were not being destroyed.

Signed-off-by: vivek <vivek.ellur@samsung.com>
Reviewed-by: Pekka Paalanen <ppaalanen@gmail.com>
Reviewed-by: Bryce Harrington <b.harrington@samsung.com>
diff --git a/clients/fullscreen.c b/clients/fullscreen.c
index 28efb15..5c5dd2b 100644
--- a/clients/fullscreen.c
+++ b/clients/fullscreen.c
@@ -562,5 +562,9 @@
 
 	display_run(d);
 
+	widget_destroy(fullscreen.widget);
+	window_destroy(fullscreen.window);
+	display_destroy(d);
+
 	return 0;
 }