Update to 3.08

Upstream changes:
3.08 2016-01-05

    - Fix a bug introduced in version 1.28 whereby a short write in Net::Cmd
      would be treated as an error instead of looping.  [David Golden, PR#24]

    - Documented the fact that Net::SMTP::auth() can accept an Authen::SASL
      object instead of a username and password.  [Jan Viktorin, CPAN RT#106183]

    - Simplified specification of INSTALLDIRS: We do not need to check the lower
      bound since we only support Perl 5.8.1 and higher anyway.

(wen)