Fix false negative bug when dropping onto same index in new container.
Remove dependence on handler shorthand, sizzle

For folks that compiled jQuery without sizzle or the 1.x shorthand methods, this should fix a couple errors.
Support vertical lists of variable height by defining a dead zone when hovering over larger items.
fix incorrectly anchored regular expressions
during ‘destroy’, remove event handlers added with ‘.on('sortupdate', …)’