* Now using db/[pre-]re/mob_random_db.txt as main file.
* Removed hardcoded limit for random monster group.
* Introduce contants for monster random group, MOBG_*. Usage in `monster` script can be '-1-MOBG_ID' to determines 'summon monster from random summon list'.
Signed-off-by: Cydh Ramdh <cydh@pservero.com>