- implement package priority (for things like Debian's pin feature)

- merge SUSETAGS_FILE_* and  REPOSITORY_REPOMD_* keys into REPOSITORY_RESOURCE

- re-order key ids

- deal with DIRSTR entries having dirid 0 (for source rpms)

- write more manpages

- forcebest pruning is not optimal: it should keep multiple packages
  with the same version instead of reducing to just one package for
  each name

IDEAS:

drop SEARCH_FILES and add SEARCH_BASENAME instead?