Setup GitHub Actions for builds

# Builds with GitHub Actions
Unittests to build on PR
Also set up behavioral tests for ML

## ML Behavioral Tests
This is a cool one, something new I've picked up.
Added desired behaviors in unittests, not checking for layer shapes, but desired behaviors from any model

### Examples
Adding a few common spelling mistakes for training data, checking output
Removing punctuation
Set desired metrics for "best" model. New PR could propose a new model/weights, and needs to pass this test

Start by reviewing the repository's existing build and unit-test entry points, then determine how ML behavioral tests and model metrics should run in GitHub Actions. Done means pull requests run the unit and behavioral checks, including the stated spelling, punctuation, and best-model metric cases, with failures blocking the build.

Written by the indexing model from the issue text.