New Feature: overlap plots from different channels.

[ubaldot]

Say that from an Arduino board I am sending something like this (comma separated values):

    int sensorValue = analogRead(A0);
    
    // Send over serial
    Serial.print(sensorValue);
    Serial.print(",");
    Serial.print(sensorValue/2);
    Serial.print(",");
    Serial.print(sensorValue/4);
    Serial.print("\n\r");

I can plot the data on 3 different graphs (one per channel, provided that I selected 3 channels from the DataFormat tab). Fine.

It would be nice to be able to plot sensorValue and sensorValue/2 on the first graph and sensorValue/4 on the second graph. i.e. to select what channel shall be plot on which graph.