Import fails in (some) spyder versions
From the vpython email list (https://groups.google.com/forum/?hl=en#!topic/vpython-users/jFiOpafJnkI):

```python
 from vpython import*
  box()
```

> there is an error showed in console:

```
  KeyError: 'default/interpreter/dedicated'
```

> but it is fine when I use Jupyter Notebook to run it.
>
> How can I fix this?
>
> The console message:

```
runfile('D:/user/Desktop/WPy64-3740/settings/.spyder-py3/temp.py', wdir='D:/user/Desktop/WPy64-3740/settings/.spyder-py3')
Traceback (most recent call last):

  File "<ipython-input-1-e68d4507caad>", line 1, in <module>
    runfile('D:/user/Desktop/WPy64-3740/settings/.spyder-py3/temp.py', wdir='D:/user/Desktop/WPy64-3740/settings/.spyder-py3')

  File "D:\\user\\Desktop\\WPy64-3740\\python-3.7.4.amd64\\lib\\site-packages\\spyder_kernels\\customize\\spydercustomize.py", line 827, in runfile
    execfile(filename, namespace)

  File "D:\\user\\Desktop\\WPy64-3740\\python-3.7.4.amd64\\lib\\site-packages\\spyder_kernels\\customize\\spydercustomize.py", line 110, in execfile
    exec(compile(f.read(), filename, 'exec'), namespace)

  File "D:/user/Desktop/WPy64-3740/settings/.spyder-py3/temp.py", line 8, in <module>
    from vpython import*

  File "D:\\user\\Desktop\\WPy64-3740\\python-3.7.4.amd64\\lib\\site-packages\\vpython\\__init__.py", line 57, in <module>
    _warn_if_spyder_settings_wrong()

  File "D:\\user\\Desktop\\WPy64-3740\\python-3.7.4.amd64\\lib\\site-packages\\vpython\\_notebook_helpers.py", line 15, in _warn_if_spyder_settings_wrong
    if not _spyder_run_setting_is_correct():

  File "D:\\user\\Desktop\\WPy64-3740\\python-3.7.4.amd64\\lib\\site-packages\\vpython\\_notebook_helpers.py", line 11, in _spyder_run_setting_is_correct
    return CONF['run']['default/interpreter/dedicated']

  File "D:\\user\\Desktop\\WPy64-3740\\python-3.7.4.amd64\\lib\\configparser.py", line 1251, in __getitem__
    raise KeyError(key)

KeyError: 'default/interpreter/dedicated'
```

diff --git a/vpython/_notebook_helpers.py b/vpython/_notebook_helpers.py
index 61c9dff..5d192fd 100644
--- a/vpython/_notebook_helpers.py
+++ b/vpython/_notebook_helpers.py
@@ -8,7 +8,9 @@ def __is_spyder():
 
 def _spyder_run_setting_is_correct():
     from spyder.config.main import CONF
-    return CONF['run']['default/interpreter/dedicated']
+    # Use this instead of accessing like a dictionary so that a
+    # default value can be supplied if the setting is missing.
+    return CONF.get('run', 'default/interpreter/dedicated', False)
 
 
 def _warn_if_spyder_settings_wrong():
['vpython/_notebook_helpers.py']