Fixed the z1pt0<->z2pt5 inversion problem
Removed the unneeded parameter intensity_measure_types_and_levels
Added a method HazardCalculation.save_sites
Renamed site_data -> hazard_site
Restored the old hazard_getters
Merged from z1pt0_vs_z2pt5
Merge pull request #1195 from gem/z1pt0_vs_z2pt5

Fixed the z1pt0<->z2pt5 inversion problem
Merge pull request #1165 from gem/1175452

Add a facility to import hazard_curves from XML files
Merged from master