[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:

- [ ] Get the existing test cases to work.
- [ ] Clean up the code for setting various cmaes settings (including diagnostics levels).
- [ ] Nice documentation about CMAES in Optimizer.h, describing possible settings.
- [ ] No memory leaks.

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).