Rewrote and reordered the examples in the Actor documentation for cla… (#635)
Rewrote and reordered the examples in the Actor documentation for cla… (#635)

* Rewrote and reordered the examples in the Actor documentation for clarity. Also added an introduction to Gym

* Minor tweaks to actor documentation

* Small changes to wording.

ujvl/ray-ng,alanamarzoev/ray,richardliaw/ray,robertnishihara/ray,ray-project/ray,ray-project/ray,pcmoritz/ray-1,atumanov/ray,alanamarzoev/ray,richardliaw/ray,robertnishihara/ray,richardliaw/ray,atumanov/ray,alanamarzoev/ray,ray-project/ray,stephanie-wang/ray,atumanov/ray,Wapaul1/ray,stephanie-wang/ray,stephanie-wang/ray,robertnishihara/ray,Wapaul1/ray,Wapaul1/ray,stephanie-wang/ray,alanamarzoev/ray,robertnishihara/ray,Wapaul1/ray,alanamarzoev/ray,robertnishihara/ray,richardliaw/ray,pcmoritz/ray-1,pcmoritz/ray-1,stephanie-wang/ray,pcmoritz/ray-1,atumanov/ray,stephanie-wang/ray,atumanov/ray,pcmoritz/ray-1,alanamarzoev/ray,richardliaw/ray,atumanov/ray,ray-project/ray,richardliaw/ray,richardliaw/ray,atumanov/ray,stephanie-wang/ray,ray-project/ray,pcmoritz/ray-1,pcmoritz/ray-1,ujvl/ray-ng,richardliaw/ray,stephanie-wang/ray,robertnishihara/ray,pcmoritz/ray-1,ray-project/ray,robertnishihara/ray,ujvl/ray-ng,ujvl/ray-ng,atumanov/ray,ray-project/ray,stephanie-wang/ray,robertnishihara/ray,ray-project/ray,robertnishihara/ray,Wapaul1/ray,Wapaul1/ray