Syntax:  chanban [channel] [operation] [parameters]
Example: chanban #feds add *.de
Handles channel bans. Following operations are supported:
add [mask1] .. [maskn]  Adds bans to channel
del [mask1] .. [maskn]  Removes bans from channel 
list [pattern]          Lists bans matching pattern
Up to 6 masks can be given for add and del.