Add geneExpr advanced options

[csiu]

Make advanced options conditional i.e. shown only if user click advanced options

options for scatter plot

• text input min colour
• text input max colour
• text input for mid colour
• radio button to use percent of expr range or percentile of points to scale colours
• way to do define midpoint

[esmason]

I didn't know you could make checkboxes like that wooah