Merge pull request #299 from jan-schreib/master

vnstat: package added
vnstat: fix cross build; add configuration file.
guile: fix -devel dependencies; added libguile subpkg and remove useless -doc subpkg.
autogen: update to 5.18.2; remove useless -doc subpkg.
vnstat: force autobuild.
autogen: unbreak build.
autogen: unbreak install.
vnstat: create /var/lib/vnstat; add systemd service.
guile: move guile-config to -devel, where it belongs.
grep: update to 2.17.