[WIP] Initial work on integating cmaes.

I started integrating CMAES into Simbody. Right now, everything is in quite a mess.

My objectives with this PR are:

- [x] Get basic CMAES functionality going.
- [x] Get the existing test cases to work (Rosenbrock, Schwefel, etc.).
- [x] cmaes readpara_t settings (e.g., convergence).
- [x] Diagnostics levels and file writing
- ~~[ ] Resuming.~~
- [x] Nice documentation about CMAES in Optimizer.h, describing possible settings.
- [x] No memory leaks.
- [x] Rewrite the test using `SimTK_TEST_` macros.
- [x] Replace abs with SimTK::abs.
- [x] Incorporate @nikohansen's updates to c-cmaes (cmaes_init_final).
- [x] In doxygen, mention that the errcmaes.dat file will be written regardless of the diagnostics level.
- ~~[ ] When to throw an exception upon failure?~~

This PR is going into the `cmaes-features` branch. There's much more to come, such as threading. However, to make this work manageable, those additions will come in subsequent PR's (still into the `cmaes-feature` branch).
> I am not using the boundary_transformation stuff (the cpp nor the header). Can I just remove it?

A minimum code change would be to `#ifdef` it out to make it easier to merge in updates later. But, it would be very easy to end up including it again by accident after an update. Best would be to ask Niko to avoid the symbol pollution. Or, he could make compilation of those functions optional, controlled by some compile-time symbol that we could unset. Ideally there shouldn't be any manual hacks by us to his code, so that we can happily include bug fixes as they come up.

I don't know what these `boundary_` functions are for, but is it conceivable that you or someone else might want to extend the Simbody CMAES functionality some day to include those functions?