check if rowLabel and colLabel are numeric arrays, if yes, then convert to Float, sort with d3.ascending param and convert back to string
Merge pull request #3 from adatao/heatmap-fix-numeric-ordering

check if rowLabel and colLabel are numeric arrays, if yes, then convert ...
Merge pull request #4 from adatao/d3_tree_diagram

D3 tree diagram
WIP: Display a tooltip when a node is hovered