Added workflows to test Linux, Windows, and Mac builds. #34

All 14 440 tests pass in 5m 39s

14 440 tests ±0 14 440 ✔️ ±0 5m 39s ⏱️ +5s
        1 suites ±0         0 💤 ±0
        1 files ±0         0 ❌ ±0

Results for commit 6feefa9. ± Comparison against earlier commit e2128e8.