sankeyD3 v0.2

• Added two new path drawing options, 'path1' and 'path2'
  based on d3-plugins PR #36 from @ghedamat and PR #40 by @cmorse.
  The standard bezier curve has difficulties when the thickness of the path is large relative to the node distance. These paths are drawn with individual bezier curves, which may not give equal area along its width, but always works.
• Added option showNodeValues to show node values above nodes
• Added option nodeCornerRadius for rounded nodes
• Added option title for titles in the upper-right corner of the plot
• Added _hover event that is fired every 2 seconds
• Added option doubleclickTogglesChildren to hide children/downstram
  nodes
• Added option xScalingFactor to scale width between nodes
• Added option xAxisDomain to make an x-axis