Idle screen support instead of pitch black screen

[kycfeel]

Hey. First of all, I'm really enjoying your project. It's working so well and smoothly as a screen mirroring server :)

This is not for a reporting issue, but for a feature request.

It will be awesome If you can add idle screen support with useful information, Something like Airplay server name, Connected Wi-Fi name, or even time and date.

Current pitch black idle screen is okay, but sometimes it makes be confused that I turned off my TV or not...