Qt: Fix Qt5 deprecation warnings

Mostly the warnings were about QString::sprintf and QFontMetrics::width.
sprintf replacement is asprintf, which annoyingly behaves differently
from sprintf - it seems to append to the string.

Not thoroughly tested, but seems to work.

win/Qt/qt_glyph.cpp

@@ -50,8 +50,7 @@ NetHackQtGlyphs::NetHackQtGlyphs()
 
 	tile_file = PIXMAPDIR "/x11tiles";
 	if (!img.load(tile_file)) {
-	    QString msg;
-            msg.sprintf("Cannot load 'nhtiles.bmp' or 'x11tiles'.");
+	    QString msg = QString::asprintf("Cannot load 'nhtiles.bmp' or 'x11tiles'.");
             QMessageBox::warning(0, "IO Error", msg);
             iflags.wc_ascii_map = 1;
             iflags.wc_tiled_map = 0;