Merge pull request #19 from tehandyb/master

changed how treemap and sankey handle negative value/no value
Merge pull request #20 from tehandyb/master

Sankey can be styled by column
changed error lables to just be a container that can be filled with any html
Merge remote-tracking branch 'upstream/master'
Merge branch 'changeToErrorLabelsTreemapSankey'