v2.0.0-alpha

- Overhaul: reorganized all source files, completely overhaul coding
- New features: gallery standalone (localhost/gallery.php), add button to delete thebpicture after it was taken and displayed on the screen, change style via admin panel, add trigger keys via config, add option to force the use of a buzzer, add option to enable CUPS button, add option to resize and crop image by center at print, use same printing settings/options for chromakeying as for normal prints, take pictures for collage one after the other with or without interruption, add version checker to admin page
- Some more bugfixes and improvements as usually