Add a quick setting tile for Android 7 to toggle the VPN on/off

[Eugene-Savenko]

1401277

http://android.wonderhowto.com/how-to/add-your-own-quick-settings-tiles-android-7-0-nougat-0173307/

User 1298523 reminded of such a possibility in Nougat: "I've always dreamed of toggling Adguard from the notification shade lol. I don't know, but maybe having a toggle would eliminate the need for the persistent notification. That would be nice."

Please check this: https://developer.android.com/about/versions/nougat/android-7.0.html#tile_api

[ameshkov]

@nkartyshov one important question about the custom tile: does it increase app process priority? http://stackoverflow.com/questions/5437044/does-android-have-a-way-to-display-process-priority-in-adb

[nkartyshov]

https://developer.android.com/reference/android/service/quicksettings/TileService.html

[nkartyshov]

done