Re-work as a proper standalone Python package

Add a setup.py so that installation is easier and a standalone CLI
script called csv-metadata-quality is provided. Now the user only
needs to run this from a virtual environment inside the project
directory:

    $ pip install .

Eventually I could publish this on PyPi when I settle on a more
appropriate package name.

See: https://packaging.python.org/tutorials/packaging-projects/
See: https://chriswarrick.com/blog/2014/09/15/python-apps-the-right-way-entry_points-and-scripts/

csv_metadata_quality/__main__.py

@@ -1,5 +1,9 @@
 from csv_metadata_quality import app
 from sys import argv
 
+def main():
+    app.run(argv)
+
+
 if __name__ == '__main__':
-    app.main(argv)
+    main()

csv_metadata_quality/app.py

@@ -15,7 +15,7 @@ def parse_args(argv):
     return args
 
 
-def main(argv):
+def run(argv):
     args = parse_args(argv)
 
     # Read all fields as strings so dates don't get converted from 1998 to 1998.0

setup.py

@@ -0,0 +1,38 @@
+import setuptools
+
+with open("README.md", "r") as fh:
+    long_description = fh.read()
+
+install_requires = [
+    'pandas',
+    'python-stdnum',
+    'requests',
+    'requests-cache',
+    'pycountry'
+]
+
+setuptools.setup(
+    name="csv-metadata-quality",
+    version="0.0.1",
+    author="Alan Orth",
+    author_email="aorth@mjanja.ch",
+    description="A simple, but opinionated CSV quality checking and fixing pipeline.",
+    license="GPLv3",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
+    url="https://github.com/alanorth/csv-metadata-quality",
+    classifiers=[
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
+        "Operating System :: OS Independent",
+        "Development Status :: 4 - Beta"
+    ],
+    packages=['csv_metadata_quality'],
+    entry_points={
+        'console_scripts': [
+            'csv-metadata-quality = csv_metadata_quality.__main__:main'
+        ]
+    },
+    install_requires=install_requires
+)