Fix 404 links in tutorial_index.rst (#622)

* Fix 404 links in tutorial_index.rst

Fixes several broken links in the Camera section of tutorial_index.rst.

Signed-off-by: Mason McGough <mcgough.mason@gmail.com>

* Fix cameras_differentiable.py typo and broken link

Signed-off-by: Mason McGough <mcgough.mason@gmail.com>

Signed-off-by: Mason McGough <mcgough.mason@gmail.com>

docs/notes/tutorial_index.rst

@@ -72,13 +72,13 @@ Simple Recipes
     * `visualize_main.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/tutorial/visualize_main.py>`_: using Timelapse API to write mock 3D checkpoints
     * `fast_mesh_sampling.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/preprocess/fast_mesh_sampling.py>_`: Using CachedDataset to preprocess a ShapeNet dataset we can sample point clouds efficiently at runtime
 * Camera:
-    * `camera_differentiable.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_differentiable.py>`_: optimize a camera position
-    * `camera_transforms.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_transforms.py>`_: using :func:`Camera.transform()` function
-    * `camera_ray_tracing.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_ray_tracing.py>`_: how to design a ray generating function using :class:`Camera` objects
-    * `camera_properties.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_properties.py>`_: exposing some the camera attributes and properties
-    * `camera_opengl_shaders.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_opengl_shaders.py>`_: Using the camera with glumpy
-    * `camera_movement.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_movement.py>`_: Manipulating a camera position and zoom
-    * `camera_init_simple.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_init_simple.py>`_: Making Camera objects with the flexible :func:`Camera.from_args()` constructor
-    * `camera_init_explicit.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_init_explicit.py>`_: Making :class:`CameraIntrinsics` and :class:`CameraExtrinsics` with all the different constructors available
-    * `camera_coordinate_systems.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera_coordinate_systems.py>`_: Changing coordinate system in a :class:`Camera` object
+    * `cameras_differentiable.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/cameras_differentiable.py>`_: optimize a camera position
+    * `camera_transforms.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/camera_transforms.py>`_: using :func:`Camera.transform()` function
+    * `camera_ray_tracing.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/camera_ray_tracing.py>`_: how to design a ray generating function using :class:`Camera` objects
+    * `camera_properties.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/camera_properties.py>`_: exposing some the camera attributes and properties
+    * `camera_opengl_shaders.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/camera_opengl_shaders.py>`_: Using the camera with glumpy
+    * `camera_movement.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/camera_movement.py>`_: Manipulating a camera position and zoom
+    * `camera_init_simple.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/camera_init_simple.py>`_: Making Camera objects with the flexible :func:`Camera.from_args()` constructor
+    * `camera_init_explicit.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/camera_init_explicit.py>`_: Making :class:`CameraIntrinsics` and :class:`CameraExtrinsics` with all the different constructors available
+    * `camera_coordinate_systems.py <https://github.com/NVIDIAGameWorks/kaolin/blob/master/examples/recipes/camera/camera_coordinate_systems.py>`_: Changing coordinate system in a :class:`Camera` object