Changes allow_overlapping_ips behavior.
Changes allow_overlapping_ips behavior.

Resolves Issue #87 by changing the overlapping IPs behavior from system wide
to within the boundaries of the subnets associated with the network.

lmaycotte/quark,asadoughi/quark,insequent/quark,alanquillin/quark,Cerberus98/quark,roaet/quark,asadoughi/quark,blamarvt/quark,lmaycotte/quark,insequent/quark,alanquillin/quark,rackerlabs/quark,Cerberus98/quark,roaet/quark,rackerlabs/quark,jkoelker/quark