Remove debug logging message
Change Edit dialog to show Back button.

I found that I forgot that you needed to push the 'Value' button to get back to the main radar
control window, so I added an explicit 'Back' button, similar to what the HDS plotter does.

The value control could be a little nicer, it is not centred.
Show and hide radar control when toolbar is clicked.

When using a touch screen the right mouse dialog entry to open the radar control is
difficult, and no function should be hidden behind a right mouse click.
Now it is only needed to open it when you have explicitly closed it. Or you click
on the toolbar button twice.