Remove duplicate assets and use other assets. Rename classes appropriately for robot-scene-env split refactoring.

examples/pybullet/gym/envs/scene_abstract.py

@@ -1,11 +1,3 @@
-# This is the only place cpp_household really imported. From other places, it is referenced as scene_abstract.cpp_household
-# If this doesn't work, the checklist is:
-# 1) Build local Bullet physics library (instructions in README)
-# 2) ldd cpp_household.so
-# 3) In case of python 2.7 when using pip2 install without -e, the C++ module gets built in python2.7/site-packages,
-# but when you have roboschool directory in cwd or in parent(s) of cwd, python2 will use that and fail to reach site-packages.
-# No such behavior in Python3. For example, no zoo scripts will work if you install without -e and run them from
-# source tree. If you copy zoo script elsewhere, it will work. (upgrade to Python3 if you can.)
 import sys, os
 sys.path.append(os.path.dirname(__file__))
 import pybullet as p