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/command/main.py

@@ -38,20 +38,20 @@ def main():
     try:
         cmd = Whipper(sys.argv[1:], os.path.basename(sys.argv[0]), None)
         ret = cmd.do()
-    except SystemError, e:
+    except SystemError as e:
         sys.stderr.write('whipper: error: %s\n' % e)
         if (type(e) is common.EjectError and
                 cmd.options.eject in ('failure', 'always')):
             eject_device(e.device)
         return 255
-    except RuntimeError, e:
+    except RuntimeError as e:
         print(e)
         return 1
     except KeyboardInterrupt:
         return 2
-    except ImportError, e:
+    except ImportError as e:
         raise
-    except task.TaskException, e:
+    except task.TaskException as e:
         if isinstance(e.exception, ImportError):
             raise ImportError(e.exception)
         elif isinstance(e.exception, common.MissingDependencyException):
@@ -80,11 +80,11 @@ You can get help on subcommands by using the -h option to the subcommand.
     no_add_help = True
     subcommands = {
         'accurip': accurip.AccuRip,
-        'cd':      cd.CD,
-        'debug':   debug.Debug,
-        'drive':   drive.Drive,
-        'offset':  offset.Offset,
-        'image':   image.Image
+        'cd': cd.CD,
+        'debug': debug.Debug,
+        'drive': drive.Drive,
+        'offset': offset.Offset,
+        'image': image.Image
     }
 
     def add_arguments(self):