IMAPServer select_FETCH incorrect for non-UID

[radix]

In select_FETCH (both today's cvs and the current
release) - line 718/667, the next UID is used as the top
value for the range.

This should only be the case if uid == 1 (i.e. we are
doing a UID FETCH). If uid != 1, then the top value
should be the message count + 1.

Replacing:
messages = parseIdList(messages,
self.mbox.getUIDNext())
with:
if uid:
top = int(self.mbox.getUIDNext())
else:
top = self.mbox.getMessageCount() + 1
messages = parseIdList(messages, top)

fixes this.

Note that this is especially a problem if very high UIDs
are used, because the later range call can run out of
memory unnecessarily.

[anadelonbrin]

See also the original SF bug.  The problem listed here was 
solved, there was an additional problem (incorrect addition 
of UID when not present on a UID FETCH) that was not yet 
solved.

Note that discussion/patches are flowing on the list at the 
moment, though.

[exarkun]

The secondary issue here has now been resolved, by way of
use of MessageSet objects, which are "automatically" the
right kind of identifier in all situations.