spf: SPF results were invalid if TXT record exceeded 25? bytes.

this appends additional TXT strings to the record (completing it)
weirdly related enhancements

* move is_ipv4_literal from plugins/helo.checks to net_utils
	so it's available for the SPF plugin

* SPF: skip HELO tests for IP literals

* SPF: when a connection has relaying permissions, use our (Haraka's) public IP in the SPF mail_from query, to determine if Haraka has permisison to send on behalf of that MAIL FROM domain.

* move the public_ip setting out of config/connect.geoip.ini to config/smtp.ini, used by GeoIP and SPF plugins.

* updated connect.geoip to use boolean config options
remove geoip config changes
spf: added [relay]context setting, and defer/deny settings for

helo/mfrom when relaying is set
spf: updated tests, added a couple more
relay: unified relay plugin
relay: docs, tests, and updates
relay: doc updates
relay: added relaying bug notice
relay: added [relay] config settings to docs
added deprecation notice to relay_* plugins
removed spf from TODO rename list
relay: validated ACL entries. Bark about errors.
Merge branch 'spf-helo' into toaster

Conflicts:
	plugins/spf.js
Merge branch 'spf' into toaster
Merge branch 'relay' into toaster

Conflicts:
	docs/plugins/relay.md
	plugins/relay.js
	tests/plugins/relay.js