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/string.py b/Lib/string.py
index 21781e7..6570fef 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -116,7 +116,7 @@
     """join(list [,sep]) -> string
 
     Return a string composed of the words in list, with
-    intervening occurences of sep.  The default separator is a
+    intervening occurrences of sep.  The default separator is a
     single space.
 
     (joinfields and join are synonymous)