[Bmi776] updated IMM/back-off notes

[Mark Craven]

Hi all,

I put an updated version of the IMM/back-off lecture notes on the web
page.  I included a simple IMM example, and I edited the back-off example
to (a) fix the bugs, and (b) better show what part of the calculations
corresponds to the lambda parameters.

Also, under the recommended reading list, I added a link to a paper
that reports on a recent empirical analysis of many motif-finding
algorithms.  I thought this would be of interest to those of you
who might apply motif-finding methods in your research at some point.

Have a good weekend.

Mark