Added pRO/twRO "Card Exchange" NPC.
Information: http://richkidherbert.blogspot.com/2013/08/card-exchanger.html

Fixed incorrect position and view for item 18771. (bugreport:8657)
http://rathena.org/board/tracker/issue-8657-item-18771-enchanced-opera-phantom-mask-is-incorrect/

Signed-off-by: Euphy <euphy.raliel@rathena.org>