wxChecksums

The attached patch fixes a class declaration that
doesn't quite follow C++ standard and gcc4.1 fails
compilation of wxChecksums due to it being stricted in
that regard.
The error is:

dlgProgress.hpp: At global scope:
dlgProgress.hpp:140: error: extra qualification
'dlgProgress::' on member 'dlgProgress'

This patch comes from
http://bugs.gentoo.org/show_bug.cgi?id=136339
and I'm just forwarding it as the Gentoo maintainer.
All credits to Miguel Marte who provided the patch.

It fixes all compilation errors with gcc-4.1.1 at least
on my system.

Thanks