Reformatted Changes file as per CPAN::Changes::Spec

Hi Jeff,

The main changes were:

* removed [ and ] from around release numbers
* consistent use of [section labels]
* consistent spacing and indenting of bullets
* merged 'not released' changes into the next CPAN release
* moved flags like *DEVELOPER RELEASE* onto the release header line

That's an impressive Changes file, which reflects the impressive work you've done on Perl::Critic!

Neil