Bump to version 1.20

Changelog:

  * d34bb7d7: add RPM specfile
  * 3cf3ba55: add service "temp_files"
  * 6b4745f8: fix bug #13: illegal division by 0
  * e3d788ed: fix bad regexp in autovacuum service
  * 0b9308bd: fix wrong curl command line options