Improve Barcode Plot Tooltip Handling

[Daniel Marsh-Patrick]

You have to be very precise with the placement of your mouse over a data point in the barcode plot, so we need to add an overlay and a suitable bisector to highlight the correct data point (similar to our line chart).

We should also provide a better way of indicating which data point is highlighted... probably by reducing the opacity of the others.

[Daniel Marsh-Patrick]

#50: Show the tooltip data point and move to the correct location. Resolves #50.

→ <<cset 8d00c7569afc>>

[Daniel Marsh-Patrick]

Reponening, as there's some odd behaviour with tracking the top-most values when using a category in the chart. Probably not too hard to fix...

[Daniel Marsh-Patrick]

#50: Was incorrectly tracking mouse coordinates for multiple categories; this has been resolved. Resolves #50

→ <<cset b7a579c68905>>

[Daniel Marsh-Patrick]

1.1.0 is now fully live in the marketplace, so closing.