[backend] bs_productconvert: use release number of package also for product
[dist] update gem dependencies so that api and webui require the same gems

Otherwise obs-server will never build
[dist] downgrade to i18n 0.6.1 as travis can't install our rpms
[dist] we need to have the rake from ruby package

no matter if henne likes or not
[dist] use bundled rake
[backend] add metacache to speed up getbinaryversions
[webui] fix the spider test - so it actually finds problems
[backend] use nosource to limit amount of download for aggregated packages
[backend] pass on nosource option in getbinarylist also in bs_srcserver
[backend] stage metacache changes in metacache.merge
[backend] fix error in addrev_meta_multiple use
[backend] fix typo in nosource commit
[backend] do not look at jobs already in progress, add support for $BSConfig::signer_maxchild_flavor