remove "Joints" from sequencer in SK projects
fixed actual (and possible) crashes accessing index 0 of potentially empty arrays
fix relative position type, and changes in position type for SK
fix contentSize editable
updated SK default project with label position centered on % of parent container
added zPosition property to nodes
update SK default project with zPosition usage
fix % relative position not calculated for some node types
fixed saving changes position slightly (of children with % positioned parent)
updated SK default project
update SB+SK submodule ref
tryfix undo changing position (display only)
test proj
update anchors when selection applied.
Physics Joints handles movable.
update UUD’s of copy/paste.
Merge branch 'develop' of https://github.com/apportable/SpriteBuilder into develop
visible and locked joints.
SK default project: bg color scales with content size
fix undo changing display position of child nodes