cppi-1.18-bp157.1.6

- Add gpg signature
- Cleanup spec file with spec-cleaner

- Update to version 1.18
  + Gnulib infrastructure updates.
  + Regenerate Makefile.in files using a version of automake that
    is not susceptible to CVE-2009-4029 or CVE-2012-3386.
- Get rid of old stuff
  + Remove BuildRoot: tag
  + Remove xz requirement
  + Remove redundant %clean section
- cppi provides translations yet; add a lang subpackage

- patch license to follow spdx.org standard

- initial package version 1.15