Putting radio buttons in Cappuccino CPTableViews

Cappuccino’s table views aren’t fully finished, so—in version 0.7.1—you can’t just add radio buttons to a table column and have them work. Nevertheless, I wanted something like this:Since I spent some time figuring out a workaround, I thought I’d save someone some time and write it up. The workaround used subclasses of CPCheckbox and CPTableColumn. [...]