Added a SourceCollector class
Merged from master
Fixed a logging level
Further cleanup
Small fix
Addressed all comments in https://github.com/gem/oq-engine/pull/1390
Renamed collector->source_collector
Merge branch 'master' of github.com:gem/oq-engine into disagg-2
Introduced a namedtuple SourceRuptureSites
Merge pull request #1390 from gem/disagg-2

Optimize the disaggregation calculator
Merge branch 'master' of github.com:gem/oq-engine into light-site-collection