1.) the meta data section of our songs need a create and a change date.
2.) the song-info class needs two properties form them
3.) the song-io natve loader/saver need to handle them
4.) bt-cmd should show them from the info method
5.) bt-edit should show them on the main-page-info and allow changing them.
1-4) are done
for 5) we could just add a label for now