Add vis to readthedocs

Summary: pytorch3d/vis has been missing. Reduce prominence of common.

Reviewed By: patricklabatut

Differential Revision: D36008733

fbshipit-source-id: bbc9fbb031c8dc95870087fa48df29410ae69e35

docs/modules/index.rst

@@ -3,7 +3,6 @@ API Documentation
 
 .. toctree::
 
-    common
     structures
     io
     loss
@@ -12,3 +11,5 @@ API Documentation
     transforms
     utils
     datasets
+    common
+    vis

docs/modules/vis.rst

+pytorch3d.vis
+===========================
+
+.. automodule:: pytorch3d.vis
+    :members:
+    :undoc-members: