api refactor: similar

Signed-off-by: Matthias Maennich <matthias@maennich.net>
api refactor: package

Signed-off-by: Matthias Maennich <matthias@maennich.net>
api refactor: db

Signed-off-by: Matthias Maennich <matthias@maennich.net>
fix deprecation warnings introduced by API changes in libarchive3

in addition clean up the LibArchive cmake description as it is included in
cmake 2.8.8 or later

Signed-off-by: Matthias Maennich <matthias@maennich.net>
remove cmake/FindLibPthread (obsolete)

Signed-off-by: Matthias Maennich <matthias@maennich.net>
get rid of GDBM (obsolete option)

Signed-off-by: Matthias Maennich <matthias@maennich.net>