build: add basic build infrastructure

pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools >= 40.9.0"]
+build-backend = "setuptools.build_meta"

setup.cfg

@@ -0,0 +1,10 @@
+[metadata]
+name = weegee
+version = 0.1.0
+
+[options]
+packages = weegee
+
+[options.entry_points]
+console_scripts =
+    weegee = weegee.__main__:main

weegee/__main__.py

@@ -447,5 +447,6 @@ def main():
     context = WeegeeContext(config)
     sys.exit(args.func(parser, args, context))
 
-
-main()
+# isn't this a tautology?
+if __name__ == '__main__':
+    main()