sysop: add South for schema migrations
sysop: rename dns_name to hostname
sysop: add Domain field
sysop: Add ReservedHostnames model.
sysop: on import, replace IPv4 NA with None/NULL.
sysop: Don't allow saving servers or rotates with reserved names.
sysop: list rotates by their fqdn.
sysop admin: add search to server list, add server count to rotate list.
admin: change header to show Tier 2 Administration.