Improved readinput_test.py
Merge pull request #46 from gem/single-getter

Support for the simplification of the risk calculators
Converting the region_constraint into a WKT polygon in commonlib, not in the engine
Fixed a small bug in the validation
Removed the annoying check is_valid_hazard_calculation_and_output
Some small simplifications
Merged from drop-risk-calculation
Substantial improvements to get_exposure
Lots of improvements and refactoring
Improved import/export of CSV files