[IMP-dev] Preparation for IMP 2.9.0 release

We're a little overdue for a new IMP stable release. Since there have been several applications of IMP published since the last stable release that currently only work with the nightly builds (e.g. NPC) and IMP 2.8 has some compilation issues with the latest CGAL and gcc, I'll be making a new release shortly - probably branching within a week or two and releasing at the end of this month. So now is a good time for any polishing, bug fixing, documentation fixes etc. (and a really bad time for any sweeping changes!)

Ben