Use new def.acl_ips and def.acl_hostnames in preference to def.acl

Split uses of admit into uses of admit_ips and admit_hostnames.
The situation with allowconnects and allowallconnects is messier -
they honour hostnames but only for exact match (no regex matching) -
so leave them for others to think about later.
Petty tidy-up: purge dangling hspace, stray () and excess blank lines.