added a jasmine test to lock issue 3101 and reused the average pixel colors
added a jasmine test to lock issue 3101 and reused the average pixel colors

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