TODO: expose a way to change the range of the clims range slider

[tlambert03]

for large data ranges (like uint16) with small intensity values, the range sliders become useless. Need a way to modify that

[gselzer]

Hmm, how much would the pan/zoom of the histograms solve things, if we had one historgram per channel?

One idea that comes to mind is the idea of "variable speed scrubbing", like how when you click on the slider and drag up, the clims move slower? Could be tough though if the range is really small, and the clims are right on top of each other...

Could also add right/double click option to set the range of the slider