Func Button for Mi Band 2

Mar 7, 2019

* WARNING! Mi Band 3 is supports the old method, but it can only detect one press and only when the screen of band is off!
* Fixed detection of a call event for connecting to a bracelet on Android 8, 9 (May request permission)
* Fixed the call silencing function on Android 8, 9 (May request enable option)
* Force enable "Always keep the program running" on Android 8.0+
* Added Exit button in top right menu
* Fixed bugs and crashes