Vanilla-style rain

im using this http://www.nexusmods.com/morrowind/mods/43656/? to replace the vanilla rain, but there was NO change ingame. tested with vanilla MW, and it works just as intended.

(RM-3404 from redmine: created on 2016-05-26 by Randy Davin, , relates #2698 (closed), duplicates #3465 (closed))