General repo cleanup

[jhollowe]

Would some effort to cleanup and streamline the contents of this repo be appreciated?

For instance, the gnulib submodule seems to never be used (a build without it cloned fully builds successfully) and all of its contents are copied in this repo. It should probably be either removed or used (and remove the local files).

It would also be useful to rewrite the README to be tailored to this repo with a catalogue of all the additional features and how to invoke them.

[voltagex]

autoreconf -i fails looking for build-aux/git-version-gen which seems to be a gnulib file.