pod-simple strict & warnings for tests

[atoomic]

perl-pod/pod-simple#118

This was merged as
perl-pod/pod-simple@409f39b

[atoomic]

pod-simple change is merged via perl-pod/pod-simple@409f39b
but not released to CPAN at this day.

We need a release before updating blead.

copy: @khwilliamson

[toddr]

<khw> It's on my list