Update README.md, fix supp data

Just some simple doco updates. Looks like a useful tool, I'll try it.

I also was interested in looking at the supplementary data for this article at
http://bioinformatics.oxfordjournals.org/content/28/17/2215.long

But the supp data appears to be in .tex format, and the figures mentioned in that tex file I cannot seem to find. Would it be possible to fix this please?

Thanks,
ben