Release steps

Because I always forget something...

1. Update NEWS.md
2. Check if scripts/bootstrapR.sh works, also with --mk-dist
3. git flow release start N.N (or git flow hotfix start N.N)
4. Update VERSION in the release branch to the current release version
5. Update Version in rcloud.support/DESCRIPTION
6. Update VERSION in the develop branch to the next release version +'-devel'
7. Fix, fix...
8. Check in artifacts
9. git flow release finish N.N (or git flow hotfix finish N.N)
10. git push from master and develop
11. git push --tags

Notes:

• We shouldn't maintain different versions of different files in different branches (except for VERSION itself). So, in particular, NEWS.md should just mention what version each feature/fix is targeted for, not what branch it was committed to.
• Everything that gets committed to the release branch will get merged both to master and develop. In principle, master should always cleanly merge to develop (except for VERSION).