Display Object: Compute border objects from number constants
Use correct variable name. Fix #230

This bug was preventing anchorX and anchorY from observing the correct
property name, and thus not work. Although this fixes the anchorX/Y issue
about the property, the layout code is not yet working correctly when anchors
are used and multiple children are placed on the same line.
Stop the pre-commit hook from duplicating Marc's author entry
Update authors file