Insert a single layout as the root of the activity window

Property definitions

android :: ui $ NativeActivity :: insert_root_layout
	# Insert a single layout as the root of the activity window
	private fun insert_root_layout(root_layout_id: Int)
	in "Java" `{
		android.widget.FrameLayout layout = new android.widget.FrameLayout(self);
		layout.setId((int)root_layout_id);
		self.setContentView(layout);
	`}
lib/android/ui/ui.nit:49,2--55,3