GUI - force UTF-8 encoding on save

Previously this wasn't forced which caused encoding issues on Windows with certain UTF-8 contents.

Author: samaaron

app/gui/qt/mainwindow.cpp

@@ -3337,14 +3337,16 @@ bool MainWindow::saveFile(const QString& fileName, SonicPiScintilla* text)
     }
 
     QTextStream out(&file);
-
+    out.setCodec("UTF-8");
     QApplication::setOverrideCursor(Qt::WaitCursor);
     QString code = text->text();
 #if defined(Q_OS_WIN)
     code.replace("\n", "\r\n"); // CRLF for Windows users
     code.replace("\r\r\n", "\r\n"); // don't double-replace if already encoded
 #endif
     out << code;
+    out.flush();
+    file.close();
     QApplication::restoreOverrideCursor();
 
     statusBar()->showMessage(tr("File saved..."), 2000);