Compatibility with Peters Algorithm

[kamranvat]

The following things need to be manually fixed before working with files generated from the s.peters_algorithm repo (develop branch) and this one (dev branch):

• An AttributeError gets raised:

".../MuJoCo_Gym/mujoco_rl.py", line 77, in __instantiateJson
    self.info_name_list = [key for key in self.info_json["environment"]["objects"].keys()] #ToDo: is this not a df? looks like a list or sth
AttributeError: 'list' object has no attribute 'keys'

This is because the dictionary is inside a list, looking into self.info_json["environment"]["objects"][0].keys()] instead works.

• Similarly, a Type error occurs:

".../MuJoCo_Gym/mujoco_rl.py", line 283, in filter_by_tag
    if "tags" in self.info_json["environment"]["objects"][object].keys():
TypeError: list indices must be integers or slices, not dict

which can be resolved by iterating over the range of the amount of objects, instead of the objects themselves.

• Lastly, a KeyError happens when looking into the .json files, I have put that issue over here, since I don't know which side this will be fixed from: (mujoco_environment compatibility) .json structure is not what mujoco_environment expects PITA-Procedural-and-Iterative-Terrain-Assembly#197 (comment)