[backend] pass on nosource option in getbinarylist also in bs_srcserver
[backend] add metacache to speed up getbinaryversions
[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
Add use_xaccel to support X-Accel-Redirect header for Nginx.