* Testing framework for timeline-based tests.
See pytests/helpers/timeline.md for a detailed description.
Fixes#832, and lays the groundwork for #833.
* Upgrade pip to most recent version before installing prerequisites on Travis.
* Add new JSON IPC implementation to be shared between the product and the tests.
Add pytest-based test support, and wire it up to setup.py and Travis.
Dial pylint down to complain about important things only.
Various minor fixes exposed by pylint.
Add basic .vscode/settings.json for linter settings (and anything else that's workspace-specific).
Fixes#831.
