--[[
-- registerHostess( {skyHostess} [, {skyHostess}] )
-- Registers a hostess who gets informed as channels are made available,
-- removed, or when players are joined/added.
--
-- args:
-- skyHostess - table
-- {
-- id - unique id for the hostess
-- callback - function called when a channel even occurs
-- (action, actionData)
-- action - string containing
-- SKY_PLAYER_JOIN|SKY_PLAYER_LEAVE|SKY_CHANNEL_LIST|SKY_CHANNEL_JOIN|SKY_CHANNEL_LEFT
-- NOTE: SkyLight seems to implement SKY_CHANNEL_LEAVE instead of SKY_CHANNEL LEFT,
-- even though its comments don't reflect this. I don't know about regular Sky.
-- actionData - table
-- {
-- channel - channel name (SKY_CHANNEL or whatever)
--
-- (action dependent:)
-- username - string - username of the player who joined/left
-- list - table - users in channel
-- }
--
-- channels - table containing channels
-- SKY_CHANNEL, SKY_PARTY, "general", etc
-- description - short string describing the addon
-- }
--]]