CForest first version

Sorry about the (void) convention in functions, this is what happens when you copy and paste ignoring the other changes :)  Other RRTstar tweaks have been also overwritten.
Maybe also add another function along these lines:
```
void addPlannerInstance(const PlannerPtr &planner)
{
    if (!planner || planner->getSpaceInformation().get() != si_.get())
    {
      throw Exception("Planner instance not constructed for the correct SpaceInformation instance");
    }
    planners_.push_back(planner);
}
```