Fix links in readme and nuImages tutorial (#459)

Author: whyekit-motional

README.md

@@ -99,7 +99,7 @@ To install nuScenes-lidarseg, please follow these steps:
 - Download the dataset from the [Download page](https://www.nuscenes.org/download),
 - Extract the `lidarseg` and `v1.0-*` folders to your nuScenes root directory (e.g. `/data/sets/nuscenes/lidarseg`, `/data/sets/nuscenes/v1.0-*`).
 - Get the latest version of the nuscenes-devkit.
-- If you already have a previous version of the devkit, update the pip requirements (see [details](https://github.com/nutonomy/nuscenes-devkit/blob/master/setup/installation.md)): `pip install -r setup/requirements.txt`
+- If you already have a previous version of the devkit, update the pip requirements (see [details](https://github.com/nutonomy/nuscenes-devkit/blob/master/docs/installation.md)): `pip install -r setup/requirements.txt`
 - Get started with the [tutorial](https://github.com/nutonomy/nuscenes-devkit/blob/master/python-sdk/tutorials/nuscenes_lidarseg_tutorial.ipynb).
 
 ### Prediction challenge

python-sdk/tutorials/nuimages_tutorial.ipynb

@@ -29,7 +29,7 @@
     "9. `object_ann` - Bounding box and mask annotation of an object (e.g. car, adult).\n",
     "10. `surface_ann` - Mask annotation of a surface (e.g. `flat.driveable surface` and `vehicle.ego`).\n",
     "\n",
-    "The database schema is visualized below. For more information see the [schema page](https://github.com/nutonomy/nuscenes-devkit/blob/master/schema-nuimages.md).\n",
+    "The database schema is visualized below. For more information see the [schema page](https://github.com/nutonomy/nuscenes-devkit/blob/master/docs/schema_nuimages.md).\n",
     "![](https://www.nuscenes.org/public/images/nuimages-schema.svg)"
    ]
   },