Remove changelog display tab

[Maia-Everett]

I think the changelog tab should be removed from the about dialog. The changelog file is severely outdated, and does not display correctly in distributions that rename the ChangeLog file to something else (for example, Debian and Ubuntu, which normally compress changelogs to debian/changelog.gz).

[amigadave]

This is now done, in the upstream development repository:

http://git.gnome.org/browse/easytag/commit/?id=269e43d4c40d0173818e800af558b33593502ed3