Openfisca-france-data

* Technical changes
- Move smic definitions in a separate module

Change the requirement version for OF-France

* New features
- Introduce a new weight variable for households

* Technical changes
- Update the SMIC parameter

* Technical changes
- Fix pypi upload by fixing package description
- Fix this [CircleCI](https://circleci.com/gh/openfisca/openfisca-france-data/663) error: `The description failed to render in the default format of reStructuredText.`

* Technical changes
- Migrate CI from Travis to CircleCI
- Reset `master` branch as default branch instead of `release/1.0.0`
- Contains [161](https://github.com/openfisca/openfisca-france-data/pull/161), [#171](https://github.com/openfisca/openfisca-france-data/pull/171), [#172](https://github.com/openfisca/openfisca-france-data/pull/172), [#173](https://github.com/openfisca/openfisca-france-data/pull/173), [#179](https://github.com/openfisca/openfisca-france-data/pull/179), [#183](https://github.com/openfisca/openfisca-france-data/pull/183), [#186](https://github.com/openfisca/openfisca-france-data/pull/186)

* Technical changes
- Various cleaning
- Introduction of MTR calculation