gm announce logic cleanup (yellow/blue)

Originally posted by [b]theultramage[/b]
http://www.eathena.ws/board/index.php?autocom=bugtracker&showbug=2145

eAthena's gm announce code uses a complicated (and undocumented) flag system for altering its behavior, like color, blue/yellow specialization, and send target. Everything is packed into a single integer and then &-ed repeatedly.

First step would be to remove the 'blue color' parameter. To make an announce blue, start the message with "blue". I am not sure if this should be extended by eathena any further...