refactored layoutsolver to use parent-child relationship instead of reference hack
refactored layoutsolver to use parent-child relationship instead of reference hack

fniephaus/babelsberg-js,psieg/babelsberg-js,psieg/babelsberg-js,psieg/babelsberg-js,fniephaus/babelsberg-js,babelsberg/babelsberg-js,psieg/babelsberg-js,babelsberg/babelsberg-js,fniephaus/babelsberg-js,fniephaus/babelsberg-js,babelsberg/babelsberg-js,babelsberg/babelsberg-js