Does not parse CSV string with a leading equals (=) correctly

Excel / Numbers and TableTool all delete leading 0's in numbers when opening CSV files.
0123 becomes 123 when opened.

To stop this from happening, when exporting the CSV, you can an equals (=) before the string:
`"yada",="0123","yada"` - Excel and Numbers will keep the leading 0 and not drop it .

This breaks up the format when opening in Table Tool:
From top to bottom, Numbers.app, TableTool, Raw CSV:

If you remove the leading `=` it displays correctly, but drops the leading 0:
From top to bottom, Numbers.app, TableTool, Raw CSV:

No source file or test is identified in the issue. Reproduce the example in TableTool, then locate the CSV import/parsing entry point and add coverage for a quoted value beginning with `=`. Done means the sample remains correctly separated into CSV fields while preserving the intended displayed value.

Written by the indexing model from the issue text.