Use the python package name for the nbextension files

Some npm package names have the form @org/packagename, which does not work so well on a filesystem, and besides, it is probably easier for the user to understand if the nbextension name matches the python package name.

Author: jasongrout

tests/testconfig.yaml

@@ -4,6 +4,6 @@ default_context:
     github_project_name: "jupyter-widget-testwidgets"
     github_organization_name: "jupyter"
     python_package_name: "ipywidgettestwidgets"
-    npm_package_name: "jupyter-widget-testwidgets"
+    npm_package_name: "@jupyter-widgets/jupyter-widget-testwidgets"
     npm_package_version: "1.1.0"
     project_short_description: "A Test Jupyter Widget Library"

{{cookiecutter.github_project_name}}/setup.py

@@ -44,10 +44,10 @@
 }
 
 data_files_spec = [
-    ('share/jupyter/nbextensions/{{ cookiecutter.npm_package_name }}',
+    ('share/jupyter/nbextensions/{{ cookiecutter.python_package_name}}',
         nb_path, '*.js*'),
     ('share/jupyter/lab/extensions', lab_path, '*.tgz'),
-    ('etc/jupyter/nbconfig/notebook.d' , HERE, '{{ cookiecutter.npm_package_name }}.json')
+    ('etc/jupyter/nbconfig/notebook.d' , HERE, '{{ cookiecutter.python_package_name}}.json')
 ]
 
 

{{cookiecutter.github_project_name}}/{{cookiecutter.npm_package_name}}.json

@@ -0,0 +1,5 @@
+{
+  "load_extensions": {
+    "{{ cookiecutter.python_package_name}}/extension": true
+  }
+}