db/fields:

Added `NumpyListField` field type.
db/models:

HazardCurveProgress.result_matrix is now a NumpyListField.
tests/db/fields_test:

Added tests for NumpyListField.
db/models:

HazardCurveProgress.result_matrix field gets a default value of `None` so that
there are no spurious exceptions if a HazardCurveProgress object is created
with default field values.
db/schema/functions:

Cleaned up the `finalize_hazard_curves` function and change the implementation
slightly. It works now. =)
calcs/hazard/general:

Refactored `finalize_hazard_curves` to use a DB function to handle the
extraction of hazard curve data and insertion of `hazard_curve_data` records.