Table-step

* Nothing large, just made the output properly indented, etc.

* Fixed bug with reading table using a variable for the filename, but asking for the
type from the extension.
* Add ability to save tables with a frequency of other than ever call.

* Restructured documentation and moved to new theme
* Fixed bug with access rows of tables with non-integer indexes as well as "current"
index
* Added support for lists of tables in pulldowns in the GUI

2021.12.22 -- Improved the handling of index columns, added formats.
* Improved the handling of the index column
* Added Save as
* Added Excel and JSON formats.

* Now supporting Python 3.8 and 3.9

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* Updated the README file to give a better description.
* Updated the short description in setup.py to work with the new installer.
* Added keywords for better searchability.