Convert all classes to "new-type" Python classes

Signed-off-by: Niels Thykier <niels@thykier.net>

britney.py

@@ -237,7 +237,7 @@ RDEPENDS = 9
 RCONFLICTS = 10
 
 
-class Britney:
+class Britney(object):
     """Britney, the Debian testing updater script
     
     This is the script that updates the testing distribution. It is executed

completer.py

@@ -15,7 +15,7 @@
 import readline
 import bisect
 
-class Completer:
+class Completer(object):
     """Completer class
 
     This class provides a readline completer for the britney hint-tester

hints.py

@@ -14,7 +14,7 @@
 
 from migrationitem import HintItem
 
-class HintCollection:
+class HintCollection(object):
     def __init__(self):
         self._hints = []
 
@@ -35,7 +35,7 @@ class HintCollection:
     def add_hint(self, hint, user):
         self._hints.append(Hint(hint, user))
 
-class Hint:
+class Hint(object):
     def __init__(self, hint, user):
         self._hint = hint
         self._user = user