Use the actual track name for the subject line when sending the track by e-mail

When you choose the option to send a recorded track by e-mail, the e-mail's subject is automatically populated with "OruxMaps track". It would be better and more useful if it actually had the track's name instead or just the date and time if no name was given e.g. 2012-04-17_1430

This would make it easier to identify the tracks in the e-mails and also, for the ridewithgps.com online service, that allows tracks to be imported via e-mail, it uses the e-mail subject for the track name.