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- Drop support for py <3.7. Min. version is py3.8.
- Updating flask web dependencies: Flask > 2, Jinja2 > 3, werkzeug > 2.0, <2.1
- Removing packaged Flask-JSGlue, replacing with custom 0.3.1 version with correct use of `markupsafe`.
- Pinning miniumum numpy version to 1.20, removing use of `np.int` and `np.float`
- Switch to `packaging.version.parse` from `distutils` for version checking
- Updates test suite to run only on DR17, and on CI on Github Actions. Removes travis yaml.