automatize the release process
This is an idea by max: have something like a "make release" that performs all required steps, like
- updating the version number in autoconf
- tagging the release in the git repo
- preparing a release change-log (for human filtering/editing)
- signing the tag (git tag -s)
- signign the release (pgp)
- uploading it?
- posting a news item on osmoocm.org?
- make sure all projects use semver
- make test library release
- make test non-library release
- update wiki with new release procedure
- make sure all projects use release helper
- improve robustness to handle mixed projects
- make sure all libraries have LIBVERSION