Are there any text editors which can read in a plain-text file containing an ASCII table and render the table wih convenient table-editing tools such as "add row," "auto-fit column width," "delete column," etc? At my job we use MS Word's track changes feature to track changes in very long documents, which is unwieldy and inconvenient. I would love to convert our documents to plain text and use SVN or git to version them and easily see diffs. However, that requires converting our tables to plain text. Fortunately, that problem is already solved - MS Word has a "table-to-text feature, and this tool http://www.sensefulsolutions.com/2010/10/format-text-as-table.html can be used to translate MS Word's output to nicely formatted ASCII tables. While that would be a great way to get all our docs to plain text format, it would be prohibitively inconvenient to actually edit ASCII tables - adding and deleting rows, widening columns when necessary, etc. Are there any text editors or plugins which can do this kind of table manipulation on ASCII plain-text tables?
Notepad++ has some basic column editing features, but it's not going to be anywhere near as convenient as Word.
I think a better alternative might be to convert to CSV or similar, use a spreadsheet program (e.g. Excel) to edit, and just always save as CSV. This would probably make the transition for users easier, and allow you to have reasonable diffs.
Emacs plus Org mode (http://orgmode.org/) does what you need. The tables can also act as spreadsheets.
Don't be put off by Emacs' reputation for being difficult to learn, that only applies when trying to do the really complicated things. For simple text editing Emacs and Org mode are really easy and tables are very straightforward.
Org mode can export to pdf and html so you can easily continue editing in another editor if necessary.