Update wxWidgets to 3.1.0

From wxWidgets master 81570ae070b35c9d52de47b1f14897f3ff1a66c7.

include/wx/defs.h -- __w64 warning disable patch by comex brought forward.

include/wx/msw/window.h -- added GetContentScaleFactor() which was not implemented on Windows but is necessary for wxBitmap scaling on Mac OS X so it needs to work to avoid #ifdef-ing the code.

src/gtk/window.cpp -- Modified DoSetClientSize() to direct call wxWindowGTK::DoSetSize() instead of using public wxWindowBase::SetSize() which now prevents derived classes (like wxAuiToolbar) intercepting the call and breaking it. This matches Windows which does NOT need to call DoSetSize internally. End result is this fixes Dolphin's debug tools toolbars on Linux.

src/osx/window_osx.cpp -- Same fix as for GTK since it has the same issue.

src/msw/radiobox.cpp -- Hacked to fix display in HiDPI (was clipping off end of text).

Updated CMakeLists for Linux and Mac OS X. Small code changes to Dolphin to fix debug error boxes, deprecation warnings, and retain previous UI behavior on Windows.

Externals/wxWidgets3/include/wx/stringimpl.h

@@ -87,13 +87,6 @@ extern WXDLLIMPEXP_DATA_BASE(const wxStringCharType*) wxEmptyStringImpl;
     #undef wxUSE_STD_STRING
     #define wxUSE_STD_STRING 1
 
-    // the versions of std::string included with gcc 2.95 and VC6 (for which
-    // _MSC_VER == 1200) and eVC4 (_MSC_VER == 1201) lack clear() method
-    #if (defined(__GNUG__) && (__GNUG__ < 3)) || \
-        !wxCHECK_VISUALC_VERSION(7) || defined(__EVC4__)
-        #define wxSTRING_BASE_HASNT_CLEAR
-    #endif
-
     typedef wxStdString wxStringImpl;
 #else // if !wxUSE_STL_BASED_WXSTRING
 
@@ -122,7 +115,7 @@ struct WXDLLIMPEXP_BASE wxStringData
   void  Lock()   { if ( !IsEmpty() ) nRefs++;                    }
 
   // VC++ will refuse to inline Unlock but profiling shows that it is wrong
-#if defined(__VISUALC__) && (__VISUALC__ >= 1200)
+#if defined(__VISUALC__)
   __forceinline
 #endif
   // VC++ free must take place in same DLL as allocation when using non dll
@@ -334,7 +327,7 @@ public:
       { return wxStdString(c_str(), length()); }
 #endif
 
-#if defined(__VISUALC__) && (__VISUALC__ >= 1200)
+#if defined(__VISUALC__)
     // disable warning about Unlock() below not being inlined (first, it
     // seems to be inlined nevertheless and second, even if it isn't, there
     // is nothing we can do about this
@@ -348,7 +341,7 @@ public:
       GetStringData()->Unlock();
   }
 
-#if defined(__VISUALC__) && (__VISUALC__ >= 1200)
+#if defined(__VISUALC__)
     #pragma warning(pop)
 #endif