x,y vs t line graphs title and labels

[sbarber2]

The "Time vs X Position" and "Time vs Y Position" line chart labels aren't quite right.

• They don't report position, the report distance moved. So they need a different title. Such as "Time vs N Distance"
• Also, the convention for graph titles I believe is dependent variable vs independent variable, and thus we would have "N Distance vs Time"
• Currently, "title" of the graph is being set using Chart.data.datasets[n].label but this is really the label for the vertical dimension dataset (the line itself, if you will), not the whole graph. So, that should just be "N" or "N Distance"
• There's no label for the horizontal dimension, this should be "Time"
• And we need an actual title for each graph, once we change the labels