Add notifications to IRCops when they get restricted information.

[jfcantu]

Addresses issue #141.

Warn IRCops that normal users can't see what they're seeing, when they get:

• /whois reply with a user's unmasked hostname (RPL_WHOISACTUALLY)
• /whois reply indicating a user is squelched/warned (RPL_WHOISTEXT)
• /whois reply with a service tag that includes a umode restriction.
• +I/+e/+b lists for a channel if XFLAG_HIDE_MODE_LISTS is set.