Some changes

[kfli716]

1. The change in EditorInstance.kt is to address a bug that double clicking space bar in English mode always produces full stop.
2. Adding "if (Build.VERSION.SDK_INT >= 28)" to KeyboardView.java allows the App to run in lower SDK level.
3. The rest are for utils that get the screen size. By the way, I scale down the height a bit when the phone is in Landscape mode so that the keyboard will not block the the whole browser now.