Direct boot aware

[Doubi88]

Since Android N, Apps must be "Direct-Boot aware", for being started before the phone is unlocked for the first time after boot. This issue is for research, if it is feasible, to use this feature for Slideshow Wallpaper and if it can access the images in locked mode. If yes, implement it.

https://android-developers.googleblog.com/2016/04/developing-for-direct-boot.html