Merge FPS-over-MCS and cobraCharmer camera logic

The fpsActor commands the mcsActor to acquire images and generate spot lists. The cobraCharmer library has a tree of classes which allow commanding one of several local camera to generate spot lists. The two interfaces are similar but not identical, and the cobraCharmer library also handles some desirable per-run (convergence test, motor map generation, etc) book-keeping.

Merge the two. I'll add an mcsActor "camera" subclass to the cobraCharmer/cobraCoach library and have the fpsActor call that. It would have been cleaner to have put all the local cameras into mcsActor at the start, but that was always going to make other development clumsier.

Correctly factoring out spot assignment functionality so that can easily be split between fps and mcs is not part of this, but that will be kept in mind.