Update packages list to install correctly on wheezy.

Make mySociety-internal file separate to keep its dual use.
Don't include --conservative, not present in old 'gem'.
Add support for SMTP authentication and TLS.

Fixes #406. Include Perl modules necessary for Email::Send::SMTP to
handle TLS/SSL, and upgrade Dir::Self due to
https://rt.cpan.org/Public/Bug/Display.html?id=88393
Switch test to use different working cobrand.
Version 1.4.2.