Fixed history state error cferdinandi#443

Adds an option to adjust scroll distance to prevent abrupt stops near…

… the bottom of the page.

Check for closest() method in event.target before calling

Pass anchor and toggle into offset()

Fixed issues with updating the URL and adjusting focus in certain sit…

…uations

Major release

Fixed document height miscalculation

Fixed endLocation() calculation error that was preventing scrolling i…

…n some applications.

Fixed global undefined

Fixed UMD for webpack