Shadow dom support

[neolivz]

Supprt for polymer & Webcomponents:

1. Will work inside shadow dom if we pass shadow dom as 3rd argument.
2. This is set as document if nothing is passed
3. All nodes who are identified by ids or classes are accessed via the shado dom node.
   Changed hard coded speed of segment going back in. This uses the same speed and effect as pull out.

Issues:
Inside shadow dom tooltips does not work properly as d3.mouse() uses d3.select('body') which will return empty and all further operations fails. I don't have a solution for this atm so basically tooltips does not work in page where you can scroll.