Merged in Jack's fixes. This brings some lines beyond 79 chars again;

Merged in Jack's fixes.  This brings some lines beyond 79 chars again;
I'll clean that up later.  Also corrected a mistake introduced by the
previous reformatting: an 'else' belonging to a 'for' was accidentally
reindented to belong to the 'if' inside the 'for'.  Note that the
module uses inconsistent indentation -- most code is indented with 8
spaces, but some of the reformatted code uses 4 spaces.  I'll fix this
later in the promised cleanup pass.