Spelling fixes supplied by Rob W. W. Hooft. All these are fixes in either
comments, docstrings or error messages. I fixed two minor things in
test_winreg.py ("didn't" -> "Didn't" and "Didnt" -> "Didn't").

There is a minor style issue involved: Guido seems to have preferred English
grammar (behaviour, honour) in a couple places. This patch changes that to
American, which is the more prominent style in the source. I prefer English
myself, so if English is preferred, I'd be happy to supply a patch myself ;)
diff --git a/Lib/UserList.py b/Lib/UserList.py
index 7bd0298..d4a8d2f 100644
--- a/Lib/UserList.py
+++ b/Lib/UserList.py
@@ -4,7 +4,7 @@
     def __init__(self, initlist=None):
         self.data = []
         if initlist is not None:
-            # XXX should this accept an arbitary sequence?
+            # XXX should this accept an arbitrary sequence?
             if type(initlist) == type(self.data):
                 self.data[:] = initlist
             elif isinstance(initlist, UserList):