* guix/ui.scm (package-specification->name+version+output): New
procedure.
* guix/scripts/package.scm (specification->package+output): Use it.
* tests/ui.scm ("package-specification->name+version+output"): New test.
* guix/ui.scm (fill-paragraph, string->recutils, package->recutils): New
procedures.
* guix-package.in (guix-package)[process-query]: Use `package->recutils'
to display package meta-data.
* tests/guix-package.sh: Adjust test.
* tests/ui.scm: New file.
* Makefile.am (TESTS): Add it.
* doc/guix.texi (Invoking guix-package): Adjust `--search'
documentation, and give an example.