Towards v0.5.0

[uniqueg]

• Add support for Python 3.7, 3.8, 3.9, 3.10 and 3.11
• Drop support for Python 2.7, 3.4, 3.5 and 3.6
• Update core and test dependencies
• Source core dependencies in setup.py from requirements.txt
• Run CI tests for all supported Python versions, in parallel
• Add type hints to all function and method signatures and critical local variables
• Fix some minor bugs
• Replace Nose test runner with Pytest
• Remove Travis CI configuration
• Remove .coverage artifacts
• Add typical Python patterns to .gitignore (from https://gitignore.io/)
• Pass through keyword args to json.dumps() in tes.models.Base.as_json(); e.g., for pretty printing (see example in feat: pass through json serialization options #41)
• Add advanced usage examples to docs

Resolves #42
Resolves #43
Resolves #21

[uniqueg]

@kellrott: mind giving me write permisions to the repo?

[kellrott]

LGTM

[uniqueg]

Not sure what this last test is, and why it isn't run? Is this still some artifact from Travis CI?

[uniqueg]

@kellrott: I've cleaned up the branch, added some advanced usage examples to the doc, and changed the target to a release branch for 0.5.0. Please check out one more time and merge if you think it's fine.

I'll add future features/fixes as individual PRs against the release branch.