Added facet_expansion query
implemented basic listener as plugin
Merge branch 'master' into listeners
Merge branch 'master' into listeners
Implemeted basic listener mechanism
Keep tabs of started threads.
Tracking oldest document
fixed bug with preserveDates from oaipmh (and other sources)
Merge branch 'master' into listeners
refactored thread start to separate methods
Merge branch 'master' into listeners
Split diskstorage into separate files
Removed stale tests
Restructured plugins
fixed bugu
Implemented basic shape computer
Merge branch 'master' into listeners
Improved defconverter performance
Added mappings for defs, adapted for elastic type "def".
Added logging