Fix wx[Check]ListBox font and margin on DPI change

These control are drawn using a wxDC. When the DPI changes, call SetFont
to update the font of the wxDC. First call wxListBoxBase::SetFont() so
m_font is updated to the new DPI, then use this font in the wxDC.
For wxCheckListBox update the margins to fit the changed checkbox size.

include/wx/msw/listbox.h

@@ -181,6 +181,8 @@ protected:
         return wxSize(w, h);
     }
 
+    virtual void MSWUpdateFontOnDPIChange(const wxSize& newDPI) wxOVERRIDE;
+
     // free memory (common part of Clear() and dtor)
     void Free();