fix colorscale bug for spans of 5-6.666
fix colorscale bug for spans of 5-6.666

aburato/plotly.js,aburato/plotly.js,plotly/plotly.js,plotly/plotly.js,etpinard/plotly.js,plotly/plotly.js,iongroup/plotly.js,iongroup/plotly.js,etpinard/plotly.js,plotly/plotly.js,iongroup/plotly.js,etpinard/plotly.js,asolagmbh/plotly.js,asolagmbh/plotly.js,asolagmbh/plotly.js