Fixes for known API differences between Win9x and NT: SetWindowsHookEx, SetWindowLong, RegisterClass, ChangeDisplaySettings/ChangeDisplaySettingsEx, ...

Fixes for known API differences between Win9x and NT: SetWindowsHookEx, SetWindowLong, RegisterClass, ChangeDisplaySettings/ChangeDisplaySettingsEx, ToAscii/ToAsciiEx, GetMessage/PeekMessage, ShowWindow. Also persists palette state through mode changes. Applies to: Windows 95, Windows 98