nvda

a4a47001 - Allow older versions of NVDA (wxPython 2) to check for and quit newer versions of NVDA (wxPython 3).

Allow older versions of NVDA (wxPython 2) to check for and quit newer versions of NVDA (wxPython 3). In wxPython 3, the class name of frame windows changed from wxWindowClassNR to wxWindowNR. NVDA uses the main frame to check for and quit another instance of NVDA. To remain compatible, create our own wxWindowClassNR window.