Track each curve axis on its own control chart

A multi-dimensional measurement records several quantities across one test, and each of them now gets its own control chart in Measurement Control.

• Added one control chart per axis, so an average, minimum or maximum is tracked against the quantity it actually belongs to.
• Added series names to the chart's axis selectors, so a curve is picked by what it measures rather than by its unit alone.
• Extended the second Y axis to the whole population of runs, so a comparison between two quantities is visible before any unit is selected.