v0.3.5-beta1

• Rearrange SimParams in Isaac Gym runner so the default interface is the same as Mujoco's.
• Now requires Isaac Gym rc4.
• Rerrunners can run multiple robots at once.
• Mujoco runner starts in real-time when not running headless. (instead of per-frame)
• Add simulation time parameter to rerunners.
• Use bounding box to position robots in the rerunners.
• Added option to Mujoco runner to start paused when not in headless mode. Added the same option to Mujoco's rerunner.
• Reliably delete temporary files created by Isaac and Mujoco runners. Mujoco's files were not deleted before.
• Add video recording to runner interface and implemented this for mujoco. Courtesy of Daniel Engbert