Add accountname support and preserve realhost when using masking

Atheme services no longer use +r to indicate authenticated users,
now the services set the "accountname" metadata. This makes that
account name visible to /iwhois

The previous hostmask support was hiding the unmasked hostname from
operators. This change preserves the host/vhost distinction for UID
lines which allows server operators to see hostnames as expected.
Display real hostname in /iwhois to bukkit opers
Set mode -r on nick change

It is the responsibility of every server to remove the 'r' flag
when a Nick change is received. Services will only publish +r
Merge pull request #69 from glguy/accountname-realhost

Add accountname support and preserve realhost when using masking