feature req: color segments

[jficz]

I'd like to be able to use different colors for different segments of the bar. Something like this:

One way to think of this would be as an extension to #67 where one would have to define something like --width 100 --overflow-width 150 if the expected overflow is 150.

Another (and preferred) way to think of this is splitting the bar to arbitrary number of segments with each one having a different color. The example image above, assuming the width of the bar is ~100, it would be something like

• for values in <0; 65> the color is white
• for values in (65; max> the color is red

Now I can only think of one practical use case: volume boost, which only needs two segments but I imagine other people might come up with something that can leverage more than two segments or even fancy things like gradients, etc.