Add GitHub Actions workflow to run tests

Restrict to Python 3.5 for now as tests fail on later Pythons.

.github/workflows/ci-build.yml

@@ -0,0 +1,43 @@
+name: CI
+on:
+    push:
+      branches:
+        - master
+    pull_request:
+
+jobs:
+  build:
+    name: Build and Test
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python: [3.5]
+        # python: [3.5, 3.6, 3.7, 3.8]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python }}
+
+      - name: Install setuptools
+        run: |
+          pip install --upgrade setuptools
+
+      - name: Install wheel
+        run: |
+          pip install wheel
+
+      - name: Install nose
+        run: |
+          pip install nose
+
+      - name: Install package
+        run: |
+          python setup.py install
+
+      - name: Run tests
+        run: nosetests --exe