Add support for command line arguments

Currently only supports specifying input and output files with -i
and -o. Eventually I'll add more options like dry run, debug, and
maybe things like forcing unsafe fixes.

csv_metadata_quality/__main__.py

@@ -1,4 +1,5 @@
 from csv_metadata_quality import app
+from sys import argv
 
 if __name__ == '__main__':
-        app.main()
+    app.main(argv)