convert NodeViewLayoutAdapter to non abstract class
composition replaces inheritance for NodeViewLayoutAdapter
immediatelyValidatingPreferredSizeCalculator
move LayoutData to new file
ContentSizeCalculator
make OutlineLayout independent from NodeViewLAyoutAdapter
organize imports
move method placeChildren to LayoutData
move method finalizeDataSet to LayoutData
inline constructor
move static instance of ImmediatelyValidatingPreferredSizeCalculator
move ZERO_DIMENSION to INodeViewLayout
move methods from NodeViewLayoutAdapter to LayoutData
LAyoutData -> VerticalNodeViewLayoutStrategy
extract method calcHighestSummaryLevel
extract method calcLevels
remove summary[]
change order of statements
separate layout for x ynd y
rename fields, methods and variables