* Show/hide accessibility overlay on scroll based on several visibility factors
* Improvements to accessibility overlay anchor view tracking
* Increase recursion limit and check for null children when walking the node tree
* Cleanup
* Hide overlay when expanding status (notification) bar
* use .Any() instead of .Count()
* Trigger overlay prompt when focusing on username field
* Adjust accessibility overlay position in response to scroll events
* Get username EditText with a single pass of the node tree, plus additional cleanup
* Replaced accessibility service notification with in-line overlay. Requires draw-over permission to be enabled (will prompt if not, though this will be enhanced in subsequent commits)
* Updated with requested changes
* Fix for FDroid build
