Added metadata and made Changes conform to CPAN::Changes::Spec

Hi,

I've added bits to the Makefile.PL to generate additional metadata:

 * set license type to 'perl' (to match what the doc says). Doing this means MetaCPAN can display it, for example.
 * provide github repo (again, this means MetaCPAN can provide it in the sidebar)
 * specify the bug tracker as RT. If you want to use github issues, change the `bugtracker` resource to
        https://github.com/karpet/rose-htmlx-form-related/issues

I also tweaked the Changes file so it will conform to CPAN::Changes::Spec &mdash; this was mainly changing the dates to ISO 8601 date format. Following this format means that various tools can more easily process your distribution automatically. You can find out more about this at Brian Cassidy's CPAN::Changes Kwalitee Service (http://changes.cpanhq.org), which is where I saw your module listed :-)

Cheers,
Neil