Announce: Pugs repository move

After years of neglected maintenance, we had to shut down the
pugs svn repository. It caused undue strain on the server that
hosted it, and made it nearly unusable.

Therefore we needed an alternative; since many active Perl 6
developers prefer git to svn anyway, we[1] decided to go with github.

Since the repository doesn't contain the Pugs compiler anymore,
it was renamed to 'mu', a pun on the type 'Mu', which in Perl 6
is the root of the type hierarchy.

Significant parts of the old pugs repo have been split up

    /                    http://github.com/perl6/mu
    /docs/Perl6/Spec     http://github.com/perl6/specs
    /t/spec              http://github.com/perl6/spectests

Other parts will slowly be split off, and moved to separate
repositories in the 'perl6' organization account. To keep maintenance
easier, all these repositories will have the same access control list.

If you want to have commit access to any of the perl6 repositories,
please send an email to me <moritz <at> faui2k3.org> with [perl6] in the
subject, or ask on the #perl6 IRC channel [2]. We are still working
on a better mechanism for adding contributors.

Since this move came rather unprepared, there are still a lot of
loose ends and broken links. I apologize for the inconvenience, and the
same time ask for help.