Expose each OMPL planner as a separate OpenRAVE planner

I modified or_ompl to create a separate OpenRAVE planner for each wrapped OMPL planner. This replaces the ability to specify the planner name in the `PlannerParameters` struct. E.g. there is an `OMPL_RRTConnect` planner that calls RRT-Connect and an `OMPL_PRM` planner that calls PRM. Both of these planners show up in `openrave --listplugins`.

I also added a `GetParameters` command that returns the list of supported parameters.
We're calling the simplifier right above that line:

     simplifier.InitPlan(robot, Planner.PlannerParameters())
     result = simplifier.PlanPath(traj)
     assert result == PlannerStatus.HasSolution

This is a minimal working example. `IdealController` will only execute timed trajectories and `RetimeTrajectory` with `LinearRetimer` is the simplest way of converting a path to a timed trajectory.

We should, however, probably have the `robot.SetPath(traj)` line in the example.