node plot reset when flags toggled

[savitakartik]

@benjeffery pointed out that toggling the node flags resets the plot,. It would be good to have the zoom unchanged when a node type is checked or unchecked.

[benjeffery]

This also happens on the mutations plot when you click log scale. To fix it we need to completely rework how we do the plots, binding the controls and making the plot once rather than making a new plot every time a control changes.

[jeromekelleher]

I think the current approach is fine, it's just the way it is.