One of the nagging problems with using nnimap as my primary mail store
is that it takes absolutely forever to enter my INBOX, as well as
causing XEmacs to allocate around 150MB of memory.

This is because I have been using the same INBOX for a long while now,
and the 'read' info range starts with '(1 . 695705)'

The code in `nnimap-request-update-info-internal' called
`gnus-uncompress-range' on this, resulting in a list containing around
seven million numbers -- an awful lot of memory, and time spent working
through it.

To address this I rewrote the code in that routine to work with
compressed ranges, rather than uncompressed, which gives me a huge
performance improvement (almost instant entry, vs ten to fifteen
seconds) and reduces the memory use significantly.


I don't think this is too performance-inefficient to include as is, and
it doesn't seem to adversely effect entry into small groups or anything
like that.

	Daniel