* Make classes that don't need to be public as package private
* Remove dead code that serves no purpose now.
* Use lambdas when needed.
* Use @UsedFromNativeCode for methods called from native code.
Change-Id: Ie34eec079366fb3ef048e0f49e03f507cdf90e97
Reviewed-by: Tinja Paavoseppä <tinja.paavoseppa@qt.io>