Graph meter coloring & dynamic scaling!

[Explorer09]

This branch needs rebasing and it's code needs some polishing.

This pull request is much bigger than #355 because it's improved and supports dynamic scaling. :)

Screenshot:

Meters that will use what I called "dynamic scaling":

• Load meter & Load average meter
• Tasks meter (a.k.a. Task counter)
• Uptime meter

Caveats:

• When merging, it's better to review changes in every commit as some of them changes variable naming in existing code for some reasons (that you might disagree; please tell me).
• The colors array in GraphData will take larger size than necessary. Although I have optimized the (tree) data structure so that it allocated no more "cells" than needed, the cell size is still large and not optimized yet. The color cells uses ColorElements enum type (which is sizeof(int) by default), and I didn't yet choose a way to optimize it. I'm asking suggestions about what to do here in code.*

*: There are two way of optimization in code: (1) changing ColorElements typedef from enum to short or char, or (2) use __attribute__((packed)) compiler directive on the enum (which will require compiler to support GCC extension), or (3) just don't bother at all.

[hishamhm]

Oh wow, this will take me a while to go through! But I'm impressed :)

[eworm-de]

Any chance we see this being merged any time soon? I really like the graph meter coloring but I do not like to resolve merge conflicts again and again (or wait for @Explorer09 to do it).

[Explorer09]

@eworm-de Hi, I was not maintaining this branch for a while, partly because @hishamhm was not interested in merging, and because I have been troubled about variable naming for a while. I would appreciate if someone likes to help making this PR branch up to date.