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 ;)

Lib/test/test_imageop.py

@@ -62,7 +62,7 @@ def main(use_rgbimg=1):
     image = imageop.grey2rgb(greyimage, width, height)
     
     # Convert a 8-bit deep greyscale image to a 1-bit deep image by
-    # tresholding all the pixels. The resulting image is tightly packed
+    # thresholding all the pixels. The resulting image is tightly packed
     # and is probably only useful as an argument to mono2grey. 
     if verbose:
         print 'grey2mono'