Fixed some UI tweaks in handler function DownHdl: now images can me moved down correctly. Also, made some
simplification in handler UpHdl: I've moved forvard the declaration of local variable nActPos.

Change-Id: I879a6394865bb8442c0621dc2789efd9eedae87c
Reviewed-on: https://gerrit.libreoffice.org/3759Reviewed-by: Andras Timar <atimar@suse.com>
Tested-by: Andras Timar <atimar@suse.com>