New feature release

In response to requests by our users, flight routes can now be saved for later use. Johannes Zellner has joined the development team. He implemented code that allows to share flight routes with other apps. If desired, you can also import flight routes in GPX format from other programs, such as "fl95.de". Johannes also implemented geoid altitude correction, which tracks the different definitions of 'sea level' used in aviation and in satellite navigation. The corrections will be applied automatically and will give more precise altitude readings.