net_utils: move is_ipv4_literal into net_utils
Merge pull request #535 from msimerson/net_utils

net_utils: move is_ipv4_literal into net_utils
net_utils: added get_public_ip, using 'stun' package
qmd: when relaying, validate MAIL FROM against QMD

and refactored the code a little, to avoid redundancy
qmd: added config:check_outbound option
qmd: move the callback to the last argument

to get_qmd_response
Merge pull request #534 from msimerson/qmd

qmd: when relaying, validate MAIL FROM against QMD
Merge pull request #536 from msimerson/net_utils

net_utils: added get_public_ip, using 'stun' package
geoip: use net_utils.get_public_ip

with backwards compat (if locally set)
geoip: added geoip-lite to optional deps

and made tests condition, based on if geoip-lite is installed