Adding Windows 32-bit and 64-bit builds

- Basic tests are working
- May need some adjustments to get all tests working
- Cleaned up bundling to take Python arch into account when building
with multiple architectures

.github/workflows/pythonpackage.yml

@@ -27,14 +27,12 @@ jobs:
         pip install -r requirements.txt
     - name: Build pycapnp and install
       run: |
-        python setup.py build # Not necessary, but shows output on stdout
+        python setup.py build
         pip install .
     - name: Lint with flake8
       run: |
         pip install flake8
-        # stop the build if there are Python syntax errors or undefined names
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics --exclude benchmark
-        # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
         flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics --exclude benchmark
     - name: Test with pytest
       run: |