wxGTK now uses gtk_init_check so wxPython can raise an exception if

wxGTK now uses gtk_init_check so wxPython can raise an exception if
there is no DISPLAY available or other initializaion problem.

wx.GetKeyState now has an implementation for wxGTK and is able to
detect the up/down or toggle state of modifier and toggle keys.

The LC_NUMERIC locale is now reset back to "C" (compatibility) when
running on wxGTK to work around the fact that GTK requires the locale
to be set to the system settings but Python depends on LC_NUMERIC
remaining compatible with "C".

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@27376 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775