I opened a bug against Growl::GNTP (https://rt.cpan.org/Public/Bug/Display.html?id=83231) to accept a timeout argument and pass it to the socket layer, but forgot I opened it just a couple hours before opening this pull request. Heh, guess that's what I get for working on a bunch of things at once.

Anyway, 3707a7a re-adds check_connection() since that seemed easier than detecting Growl::GNTP's version and only using check_connection() when Growl::GNTP didn't support a specifiable timeout. Unfortunately, there's no way to reach into Growl::GNTP to set the socket timeout, since its socket instances are all function-local.