Don't cause keyboard errors in empty grids.

When the grid has no columns, don't try to respond to incremental
searches or other keyboard actions.

I was mocking up a form with no columns in my grid for now, and
hit a traceback because self.Columns was empty.
Display the appName and appVersion in About.

Instead of just saying "Dabo" as the header in the about screen,
Fill in the appName and appVersion from the App object. Also,
by default fill in app.addToAbout using the app's docstring.