Options for columns of Table.
type of column, which decides how table cells are rendered.
By default the column renders readonly text.
Custom, this function will be used for renderering
table cells under the column.
The function will be called with
ondraw(painter, rect, value).
column of table model to show.
By default the index of table's newly-added column will be used.
Initial width of column.
Using -1 will use auto-size. By default -1 is used.
On Linux setting the width of last column does not work, it always resizes to fill the space. It is recommended to use -1 for last column to have consistent behavior between platforms.