Fix Copyright information in qglinfo about dialog

Change from Nokia to Digia, and update the year. Also remove mentioning
of GPL license since it is available under multiple licenses ...

Change-Id: I335f4c6a718f6134618fceb1f623c4d6eae0c528
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Style About dialog similar to the other tools

Don't use hard-coded fonts or sizes. Also rename button from "Ok" to
"Close", and make the dialog non-resizable.

Change-Id: Iec3b79a9bbc2098c12223ac25786fe9804155806
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>