README update, code linting changes

- PEP8 fix
- Remove useless parens
- Docstring fixes
- RegEX: remove unneeded escape character
- accuraterip-checksum: output usage to stderr in case of wrong invocation

Signed-off-by: JoeLametta <JoeLametta@users.noreply.github.com>

whipper/common/program.py

@@ -578,6 +578,8 @@ class Program:
         :type overread: bool
         :param what: a string representing what's being read; e.g. Track
         :type what: str or None
+        :param coverArtPath: path to the downloaded cover art file
+        :type coverArtPath: str or None
         """
         if trackResult.number == 0:
             start, stop = self.getHTOA()