Fix right-alignment (tempo-markers) and oversized bounding-boxes.
_width_correction should be removed after testing on various systems.
Glib::RefPtr<Pango::Context> context = _canvas->get_pango_context();
Glib::RefPtr<Pango::Layout> layout = Pango::Layout::create (context);
-#ifdef __APPLE__
+#if 0 // def __APPLE__ // Looks like this is no longer needed 2017-03-11, pango 1.36.8, pangomm 2.34.0
if (_width_correction < 0.0) {
// Pango returns incorrect text width on some OS X
// So we have to make a correction