Run as daemon after first binding; don't record leases defined in config file; rememb...

Run as daemon after first binding; don't record leases defined in config file; remember leases even if the interface to which they're attached isn't presently configured; preferentially select a lease offer if it's for the address we asked for; if we don't successfully bind, iterate through list of remembered leases and see if one works; arp for lease before accepting it and send dhcpdecline if it's bogus; various bug fixes