Breaking changes
* In YAML tests:
- Deprecate and remove the `IGNORE_` prefix
- Deprecate and remove the `ignore` property
* In the YAML test runner:
- Deprecate and remove the `force` option (`-f` in the shell script)
- Deprecate and remove the `default_absolute_error_margin` option (`-M` in the shell script)
- Deprecate and remove the `default_relative_error_margin` option (`-m` in the shell script)
New features
* Add `Reform` and `numpy.round` (as `round_`) in the model API
* Introduce `tax_benefit_system.apply_reform(reform_path)`
* Allow YAML tests to declare the reforms they need to be executed (through the `reforms` property)
Technical changes
* Move the `dummy_extension` to `OpenFisca-Dummy-Country`
* Test `openfisca-run-test` script