Assume UTF8 for vtkCarbonRenderWindow::SetWindowName

Since VTK now uses UTF8 in other places, use it here too instead
of ASCII.  This is backwards compatible.

Change-Id: I32dc7174e1460f27c8e73e6fb6b8982f2d35d0b7

Rendering/OpenGL/vtkCarbonRenderWindow.cxx

@@ -332,7 +332,7 @@ void vtkCarbonRenderWindow::SetWindowName( const char * _arg )
     {
     CFStringRef newTitle =
       CFStringCreateWithCString(kCFAllocatorDefault, _arg,
-                                kCFStringEncodingASCII);
+                                kCFStringEncodingUTF8);
     SetWindowTitleWithCFString(this->RootWindow, newTitle);
     CFRelease(newTitle);
     }