App QA 2: Manhattan plot

[jackparmer]

• Notice that these threshold lines are at different levels when the app loads. They shift downward
  
  I think the graph initial load values for these lines is different from the defaults set in the slider callbacks.. then the slider callbacks get called on Dash app load so shift downwards... Just a guess on what is going on
• Slider -> graph is still too slow to update... Taking 5 seconds. Can we use Dash clientside here? clientside callback interface dash#672 Can we use a much smaller dataset/graphs so that is doesn't take 5 seconds to redraw on? Would also be cool if we could put in a loading spinner on update
• Would be nice if these chromosomes were spaced out a bit:
  
• Autoscale is a bit weird. Can we limit the zoom-out upper bound? Probably don't also need these 2 axes lines: