Merge pull request #506 from msimerson/config

Nice. Merged.
helo: results processing, skip checks after 1st pass
helo: added match_rdns, mismatch, reject, results store

added reject=true config option
added helo_init, which refreshes config & tracks multiple invocations
split valid_tld from no_dot into it's own function
when skipping tests, provide a reason
helo: remove helo_ prefix from function names
helo: improved cfg option handling
helo: added first test
helo: tests, tests, and more tests!