Skip Perl Critic, Pod and Pod Coverage tests unless AUTHOR_TESTING

Even after telling Perl::Critic to use its default policy configuration
we may still see unexpected failures from CPAN Testers resulting from
different versions of Perl::Critic having different policies.

Pod tests may likewise have unexpected failures caused by users having
different versions of the testing modules to the author.

None of these tests are relevant to users anyway, so disable them by
checking for $ENV{AUTHOR_TESTING}, as per the Lancaster Consensus.

Resolves CPAN RT#99399.
Release 3.00
Bump version
use version 1.999 of IO::Socket::SSL, because it protects against bad versions of IO::Socket::IP (0.30)
Tidy up following 042ff9d728

Two IO::Socket::SSL version bumps were missed (probably because they were
wrong to start with, saying 1.944 instead of 1.994!). Also, update Changes.
Release 3.01
Bump version
Add credit for fixes in v3.01
Fix $smtp->auth($sasl)

Try the AUTH mechanism (if present) in the Authen::SASL object before
falling back on other mechanisms.

Resolves CPAN RT#99415.
Don't run interactive prompt() in Makefile.PL when in PERL_CORE
Release 3.02
Bump version
No need to escape . in a character class

Spotted by "eponymous alias" <eponymousalias@yahoo.com>.
Reformat Changes file as per CPAN::Changes::Spec
Add optional Changes testing (skipped unless AUTHOR_TESTING)
Update CPAN Request Tracker URL for reporting bugs
No need to repeat checks for IO::Socket::SSL in t/*_ssl.t

We have already skipped all tests if !can_ssl() so there is no need to
repeat what it checks. Nor is there any need to test if
IO::Socket::SSL::Utils can be loaded and contains a required function: We
can safely assume this is true if we've already checked that a suitable
version of IO::Socket::SSL is available. All we need to do is to actually
load IO::Socket::SSL::Utils since IO::Socket::SSL doesn't load it itself.
Avoid "Argument ... isn't numeric in subroutine entry" warnings

Testing IO::Socket::* $VERSIONs can cause "Argument ... isn't numeric in
subroutine entry" warnings on some older perls (e.g. 5.8.8), even when
version.pm is updated to the latest version, if the module in question has
a "development" style version number like "1.79_01".

Fixes one problem reported in CPAN RT#100020.
Increased minimum required Socket version from 1.3 to 2.016

This turned out to be the cause of the remaining problem on CPAN RT#100020,
but only on machines having IO::Socket::IP (and even then that worked fine
on my machine, so it is probably OS dependent).

Don't restate the minimum required version everywhere that Socket is used.
It seems like overkill (and maintenance hassle) in a world where various
CPAN shells do a good job of installing required versions of prerequisite
modules, and it already wasn't done for IO::Socket (which also has a minimum
required version).
Remove unnecessary scope for "no warnings 'once'"