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/image.c b/clients/image.c
index 054979d..112b93d 100644
--- a/clients/image.c
+++ b/clients/image.c
@@ -424,5 +424,7 @@
 	if (image_counter > 0)
 		display_run(d);
 
+	display_destroy(d);
+
 	return 0;
 }