DisaggMixin now uses Calculator for it's base class.
DisaggMixin now uses Calculator for it's base class.


Former-commit-id: 96be3a1d8df2b9b75fec555a8b5e745d9f7de39c [formerly 55b6fda77db9611e69d0209f614acdc26e9a33a4]
Former-commit-id: eacedf6a6bf4367b6f0409ed591ab34d989fa520
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine