PATCH: Bring blead into sync with version.pm 0.9905 CPAN release

Attached is a patch to bring blead into full sync with the 0.9905 
version.pm release, which I have just pushed to CPAN.  This completes 
the work that Father Chrysostomos started in

   https://rt.cpan.org/Ticket/Display.html?id=88458

to extract the XS code in such a way that it can be trivially included 
in the Perl core and exactly the same code can be used for the CPAN release.

As part of this effort, I made a number of changes:

1) All Perl releases prior to v5.10.0 now use exclusively the pure Perl 
version::vpp code;

2) I made version:vpp functionally equivalent when use'd directly as 
when use'd as the implementation method for version.pm itself.  I had a 
request some time ago to always install version::vpp so that module 
authors could use that directly.

3) I went through all of the XS code paths to pre-validate the value and 
caught another couple of edge cases (passing extremely large unsigned 
ints, passing in an array/hash ref).

Thanks

John

• PATCH: Bring blead into sync with version.pm 0.9905 CPAN release by John Peacock
• Re: PATCH: Bring blead into sync with version.pm 0.9905 CPAN release by Father Chrysostomos
• Re: PATCH: Bring blead into sync with version.pm 0.9905 CPAN release by John Peacock
• Re: PATCH: Bring blead into sync with version.pm 0.9905 CPAN release by Karl Williamson