Blocked guildcards are not included in packet 0x03DC

[dcrodman]

Sylverant includes blocked guildcards as part of the guildcard data chunk sent via series of 03DC packets (though Newserv and Tethealla skip them). The friend guildcards have been implemented but at some point the blacklist will need to be implemented as well.

The blocked guildcard structure appears to be the same as the guildcard structure defined by the GuildcardEntry struct minus the padding and comment. The whole data chunk includes 29 of them (for 264 bytes each, hence the 0x1DE8 placeholder in GuildcardData).