Merge pull request #417 from msimerson/spamassassin

Merged.
Fix typo
steve's fcrnds plugin
renamed, refactored, added docs, config

renamed to connect.fcrdns
abstracted blocks of code into isGeneric_rDNS() and resultsToNote()
added resultsToAuthResults(), adds iprev=nnn to Authentication-Results
added Public Suffix List to net_utils

added exported methods isPublicSuffix and getOrganizationalDomain
added punycode TLD detection
fcrdns: use PSL for TLD detection, pass FCrDNS if

the first 3 octets of the remote IP match DNS results
fcrdns: honor whitelists form rdns_access
fcrdns: noted that iprev is saved to Auth-Res header
fcrdns: bug fix, corrected variable name
fcrdns: add disconnect_timeout setting
fcrdns: more refactoring, inherit note.js