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/sre_constants.py b/Lib/sre_constants.py
index ef32c32..c2cecdf 100644
--- a/Lib/sre_constants.py
+++ b/Lib/sre_constants.py
@@ -172,7 +172,7 @@
 # flags
 SRE_FLAG_TEMPLATE = 1 # template mode (disable backtracking)
 SRE_FLAG_IGNORECASE = 2 # case insensitive
-SRE_FLAG_LOCALE = 4 # honour system locale
+SRE_FLAG_LOCALE = 4 # honor system locale
 SRE_FLAG_MULTILINE = 8 # treat target as multiline string
 SRE_FLAG_DOTALL = 16 # treat target as a single string
 SRE_FLAG_UNICODE = 32 # use unicode locale