Update CScreen to work better with wxWidgets 3.X for GTK
* Change the super class to a documented type of wxScrolled<>. * Change deprecated calls to PrepareDC to DoPrepareDC. * Use m_DeviceContext.SetBackground() to set the brush for Clear()
Authored by: david_costanzo 2016-05-21
Parent: [r4086]
Child: [r4088]