[IMP-dev] Other optimizers and salilab only modules

When trying to figure out why some of my optimizations were failing, I wrapped a number of optimizers available in GSL so they can be used in IMP. These include another implementation of CG, a quasi-newton optimizer and simplex (I mostly wanted CG, but the other came for free). We can't ship the wrappers (unless we want to ship a GPL-ed special edition of IMP along with the LGPL one), but they might be useful to people to experiment with. If others are interested, I'll add a salilab_modules directory in IMP for such in-house code which would not be released (we can figure out how to make it inaccessible to the outside world when such is needed).