copy_profile uses lib/append_files

append_files contains a list of which should be appended instead of overwritten
by traits
instacam -> special_purpose/instacam
add support for overlay
make init_overlay more resilient
fix perms of all_led and led
add ffmpeg special_purpose trait
add trait for installing overlay packages
root_overlay now utilizes firstrun to prepare the overlay
add profile nfc_login
add profile shack_streamer
in traits - ignore private traits
fix naming bug in append_files
init_overlay - doing an actual unmount after finishing
fix firstrun module