Removed the properties ProbabilityEventBased.aggregate_losses and ScenarioRisk.aggregate_losses in favor of a single function
Big refactoring of scenario damage: removed confusing microfunctions and unused functions; converted functions into methods when appropriate
Fixed the damage_distribution_by_taxonomy aggregation
Fixed a mutation issue
Really fixed the mutation issue in aggregate_losses
Implemented mean and std as properties of ScenarioRiskOutput
Merge pull request #27 from gem/1096880

Refactor the aggregation mechanism to avoid relying on side effects