Wildtype amino acid label issue in certain datasets

[WillHannon-MCB]

The X that labels the wildtype amino acid identity in the heatmap disappears when you click on the same point in the line plot twice. This only happens when datasets have measurements for the wildtype amino acid.

I would guess that this is caused by the heatmap <rect> position updating when the heatmap updates causing the <rect> to appear above the wildtype <text> in the SVG. I think this could be solved by wrapping the wildtype <text> element in a separate group and making sure this group is above the heatmap <rect>'s in the DOM.