Dismiss wxSplashScreen on any user input, not necessarily on splash itself.

Dismiss wxSplashScreen on any user input, not necessarily on splash itself.

Use wxEventFilter to remove the splash screen as soon as any user input is
detected anywhere in the application, not necessarily over the splash screen
itself.

This ensures that the splash screen disappears as soon as the user starts
working with the application instead of sticking around and covering the main
window.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69796 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775