Update package meta data

[Michael Heimpold]

• the package release tarball 0.2.6 contains still the version 0.2.5 in configure.ac
• maintainers e-mail address should be updated
• man page also contains version tag 0.2.5
• Changelog could be updated

Sorry to not create a PR, but I'm limited in time at the moment.

[Reimar Döffinger]

Thanks for pointing it out. I won't update that release (I don't like moving tags around and it's not that critical), but I have writing a proper release script on my TODO.
Trying to remember what things to manually change just doesn't really work.