Remove joints from table to avoid that Fetch can slide it to cheat (o…

…penai#962)

* Remove joints from table to avoid that Fetch can slide it to cheat

* Bump Gym version

* Bump version

* Do not bump Hand

Fix installation issue on Linux

Include missing assets

New robotics environments (openai#912)

bump gym version

Migrate to mujoco-py 1.50 (openai#834)

* all envs run offscreen

* render works

* changed mujoco-py version

* Bump versions

* Update version and README

* Same versioning for all mujoco envs

* Fix typo

* Fix version

* Bump version again

* Revert "Fix version"

This reverts commit decc577.

Cut release for v0.7.4

Bump version