Modified to catch some errors, mirror d3.extent behavior if necessary and handle arrays of arrays for multiple data series.
Modified to catch some errors, mirror d3.extent behavior if necessary and handle arrays of arrays for multiple data series.

bjedrzejewski/d3fc,djmiley/d3fc,fxcebx/d3fc,fxcebx/d3fc,fxcebx/d3fc,janakerman/d3-financial-components,bjedrzejewski/d3fc,bjedrzejewski/d3fc,alisd23/d3fc-d3v4,djmiley/d3fc,alisd23/d3fc-d3v4,alisd23/d3fc-d3v4,janakerman/d3-financial-components,djmiley/d3fc