Multiple DNS servers can be specified, separated with ';'. Most
clients will consider only the 1st one listed. The special 'auto'
keyword is updated to advertise all nameservers used by the DHCP
server.
In addition to dynamic IP allocation from a pool of addresses, provide
a way to configure clients with static IPs configured in ini file: new
section "static_dhcp" allows to configure static mapping MAC ->
IP. All clients in these sections will be allowed by default (ACLs)
unless explicitely disabled in "mac" config section.
If pool_count is set to 0, only static IP allocation is supported, but
pool_start must still be defined to be a valid IP address in the local
network (eg. IP of the DHCP server).
