ipam-client improvements
ipam-client improvements (#32) * ipam-client: add vlan id in get_subnet_* methods Standardize vlan id fetching in all methods * ipam-client: add get_subnet_with_ips method This allows to fetch a whole subnet with all allocated ip addresses. * use a buffered cursor for mysql This prevents "unread result" issues * handle /0 subnets DB will return an empty string, translate it to 0