Prune trailing whitespaces from code and documentation

They are redundant in all pruned cases and sometimes even create some
problems, e.g., when one tries to jump through paragraphs in vi.

Signed-off-by: Eygene Ryabinkin <rea@codelabs.ru>

offlineimap/repository/LocalStatus.py

@@ -91,7 +91,7 @@ class LocalStatusRepository(BaseRepository):
         return folder
 
     def getfolders(self):
-        """Returns a list of all cached folders.  
+        """Returns a list of all cached folders.
 
         Does nothing for this backend. We mangle the folder file names
         (see getfolderfilename) so we can not derive folder names from