Removed sa_period and sa_damping from gmf_scenario
Removed gmf_scenario.result_grp_ordinal
Implemented a new distribution per block of sites in the scenario hazard calculator
Cosmetic change
Merged from master
Fixed the qa tests for scenario_risk
Added a comment
Merge pull request #1055 from gem/simplify_gm_scenario

Fix the memory occupation issue for the scenario_risk calculator