15.3: Fix for interference with video recording apps. To detect when the camera is in use, camera permission is needed. This is optional in Android 6+, but if you don't give permission, Shush! can't tell that you're using the camera, and may pop up during video recording.
15.2: fix for failure to pop up on some devices. Temporarily removed camera permission and the associated check for "camera in use", as this was contributing to the problem. Will add the camera check back later.