Remove explicit inheritance from object

Summary:
All classes implicitly inherit from `object` since Python 3, so remove unnecessary explicit inheritance.

From the [official documentation](https://docs.python.org/3/library/functions.html#object):

> `object` is a base for all classes.

Reviewed By: nikhilaravi

Differential Revision: D28942595

fbshipit-source-id: 466c0d19d8a93a6263e7ad734c3e87160cfa6066

projects/nerf/nerf/stats.py

@@ -11,7 +11,7 @@ from matplotlib import colors as mcolors
 from visdom import Visdom
 
 
-class AverageMeter(object):
+class AverageMeter:
     """
     Computes and stores the average and current value.
     Tracks the exact history of the added values in every epoch.
@@ -65,7 +65,7 @@ class AverageMeter(object):
         ]
 
 
-class Stats(object):
+class Stats:
     """
     Stats logging object useful for gathering statistics of training
     a deep network in PyTorch.

pytorch3d/structures/meshes.py

@@ -7,7 +7,7 @@ import torch
 from . import utils as struct_utils
 
 
-class Meshes(object):
+class Meshes:
     """
     This class provides functions for working with batches of triangulated
     meshes with varying numbers of faces and vertices, and converting between

pytorch3d/structures/pointclouds.py

@@ -5,7 +5,7 @@ import torch
 from . import utils as struct_utils
 
 
-class Pointclouds(object):
+class Pointclouds:
     """
     This class provides functions for working with batches of 3d point clouds,
     and converting between representations.

pytorch3d/structures/volumes.py

@@ -8,7 +8,7 @@ from ..transforms import Scale, Transform3d
 from . import utils as struct_utils
 
 
-class Volumes(object):
+class Volumes:
     """
     This class provides functions for working with batches of volumetric grids
     of possibly varying spatial sizes.