[yt-dev] Issue #975: Quickstart introduction notebook has incorrect dataset URLs (yt_analysis/yt)

[mordecai]

New issue 975: Quickstart introduction notebook has incorrect dataset URLs
https://bitbucket.org/yt_analysis/yt/issue/975/quickstart-introduction-notebook-has

mordecai:

Reporting Version: None

In the Quickstart documentation, the notebook _Introduction.ipynb has three 
dataset download curl commands. All of them need ".gz" appended to the end 
for consistency with the actual filenames at yt-project.org/data.  Otherwise
the curl seems to fail silently.