[yt-dev] Issue #709: Remove vestigial welcome section. (yt_analysis/yt)

[Nathan Goldbaum]

New issue 709: Remove vestigial welcome section.
https://bitbucket.org/yt_analysis/yt/issue/709/remove-vestigial-welcome-section

Nathan Goldbaum:

There is some material in the `welcome` folder that is no longer part of the docs toctree and should be removed.  Useful material should be copied to documents that are in the new toctree.