mod_access overhaul. Network/netmask and CIDR syntax. Critical path

speedups.  Forced double-reverse DNS.  Deprecate the "allow from
user-agents" syntax.  "HostnameLookups double" support.

PR:		762, 860
Reviewed by:	Paul Sutton, Marc Slemko (well he liked the double reverse part)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@78820 13f79535-47bb-0310-9956-ffa450edef68