* github workflow: add checkout step and use makefile target for file

setup
* add README.rst to gitignore
* makefile: validate wheels, run python example, add README.rst option
* usage.py: fix output directory and simplify for loop
* setup.py: remove unused os module
* setup.cfg: syntax fix

.github/setup.sh

@@ -1,5 +0,0 @@
-#!/bin/bash
-
-cat ../README.md | grep '^# IMCtermite' -A 50000 > ../python/README.md
-cp -r ../lib ../python/
-cp -v ../LICENSE ../python/

.github/workflows/pypi-deploy.yml

@@ -11,10 +11,9 @@ jobs:
     name: Prepare environment for wheel builds
     runs-on: ubuntu-20.04
     steps:
-      - name: Prepare files
-        run: |
-          chmod +x "${GITHUB_WORKSPACE}/.github/setup.sh"
-          "${GITHUB_WORKSPACE}/.github/setup.sh"
+      - uses: actions/checkout@v2
+      - name: Prepare wheel build
+        run: make -C python/ setup
 
   build_wheels:
     name: Build binary wheels on ${{ matrix.os }}