Convert docstrings to reStructuredText

This commit also includes:

  - whitespace / code formatting fixes
  - slight syntax related changes: except <exception_name>, e -> except <exception_name> as e
  - 3 pointless instructions instances have been rewritten [sorted] (spotted by semi-automatic check)

The unrelated changes shouldn't have any real impact on whipper's behaviour.

whipper/program/flac.py

@@ -5,9 +5,15 @@ logger = logging.getLogger(__name__)
 
 
 def encode(infile, outfile):
-    """
-    Encodes infile to outfile, with flac.
-    Uses '-f' because whipper already creates the file.
+    """Encode infile to outfile, with flac.
+
+    Uses ``-f`` because whipper already creates the file.
+
+    :param infile: full path to input audio track.
+    :type infile: str
+    :param outfile: full path to output audio track.
+    :type outfile: str
+    :raises CalledProcessError: if the flac encoder returns non-zero.
     """
     try:
         # TODO: Replace with Popen so that we can catch stderr and write it to