Updates for iOS 15 and some UI improvements. Also some Bug fixes

Privacy Information update for new iOS versions

Wooow! The second update, it's about saving graphs in files, so now you can: - save your graphs in files and open them whenever you like to. - the settings of the visualization are now also saved in a file, so you don't have to set them after every launch of the app. - the files are automatically updated, when ever you change something in the app. - there now is a tutorial introducing the app. Other new features: - random colors for objects, to better differentiate them - duplicating objects - intersection lines with coordinate levels of planes

Wooow! The first update, it's mainly about calculations, because just entering and displaying objects is boring, so now you can: - calculate and display the intersection point / line, the distance and the angle between 2 objects - the results of a calculations can be added as an object and be further edited - of course, you can also choose the color for calculations - the different types of planes / lines (e.g. normalized form, linear equation form, ...) are automatically converted Other new features: - the use of the app on the iPhone has been improved and adapted - the axis that points up is now selectable (by default, the Z-axis now points up)