Require Exporter version 5.57+

Hi Ito-san,

In a number of the modules, you are importing the import() function from Exporter. But this feature was only available in Exporter 5.57 and later, so I changed all the use statements to require at least that version.

I also added "use strict" and "use warnings" to the two modules which didn't have it. This will remove another fail from CPANTS :-)

BusyBird::Util has "use 5.10.0", but it looks like it actually just requires 5.8.0, unless I've missed something? I was going to add explicit Perl version requirements in every module, setting it to 5.008, but thought I'd check with you first.

Cheers,
Neil