Openfisca-country-template

* Tax and benefit system evolution.
* Impacted periods: all.
* Impacted areas: `taxes`.
* Details:
- Implement housing tax minimal amount.

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* Minor change.
* Details:
- Add metadata to parameters.

* Minor change.
* Details:
- Make bootstrap script portable.

* Tax and benefit system evolution.
* Impacted periods: all.
* Impacted areas: `demographics`.
* Details:
- Improve reliability and accuracy of `age` formula.
- Improve variables comments.

* Minor change.
* Details:
- Upgrade openfisca.org references to HTTPS.

* Minor change.
* Details:
- Add situation example using YAML.

* Technical improvement.
* Details:
- Continuously deploy Python3 package.