refactor Spatial+Node: replace TreeNode with inlined singly linked list
add SpatialIterator
make sibling pointer private (doesn't make sense in Node class)
move setFirst(), setLast() to Node class, rename toFront(), toBack()
refactor, clean up
work on Sprite class
clean up
simplify CanvasRenderer
work on affine transform
sprite strip is now a sprite atlas format
work on sprite api
work on texture atlas
work on sprite api
work on sprite api
replaced TextEffect with SpriteFont
replaced reserved keyword 'char'
work on scene graph
remove api package
kernings node might be missing
parse texture size and scale from meta data