High Stock Navigator-only Chart

• Built from http://codepen.io/roblabs/full/xErGqq/

Usage cases

1.  Click on area of graph, either in the window or out
2.  grab 'bottom' of window, and move left & right
3.  grab 'right' extreme of window, and make window larger.   Should snap to default window width
4.  grab 'right' extreme of window, and make window smaller.  Should snap to default window width
5.  grab 'left'  extreme of window, and make window larger.   Should snap to default window width
6.  grab 'left'  extreme of window, and make window smaller.  Should snap to default window width