added TAP support in output

TAP is a Test Anything Protocol. It is a format used for test output. See 
It would be nice to implement TAP for smtpscript. It allows to push test results to test portals like Tapper (tapper-testing.org).

Now output looks like:

$ smtpscript/smtpscript -t regression-mailfrom  
# proc init-helo
# smtpscript is an SMTP testing framework

TAP version 13
ok 1 - mailfrom-empty
ok 2 - mailfrom-without-local
ok 3 - mailfrom-without-domain
ok 4 - mailfrom-max-local-part1
ok 5 - mailfrom-max-local-part2
not ok 6 - mailfrom-max-domain1 # unexpected response code2: 553 Sender address syntax error
not ok 7 - mailfrom-max-domain2 # unexpected response code2: 553 Sender address syntax error
ok 8 - mailfrom-max-email
ok 9 - mailrom-min-email
not ok 10 - mailfrom-special-symbols1 # unexpected response code2: 553 Sender address syntax error
ok 11 - mailfrom-special-symbols2

and from my point of view it is more readable than earlier :)