Update installation instructions for crux

Fix distro on new Arch linux installs. Fixes #336

Added support for various music players

Fixed percent not displaying in cpu_display

Expanded distro_shorthand to support non-LSB solutions

OpenBSD's battery status get back into the BSD case

Maybe the original commiter forgot the * so s/he decided to get OpenBSD's
case nest into the `$os` instead of `$distro`.

I suspect the original reason that because OpenBSD's `$distro` output
is `OpenBSD $(uname -m)` instead of just `OpenBSD` so the results didn't
appear.

Anyway, for consistency, I decided to bring OpenBSD's battery case back
to the `$distro` case, add a very little fix (which is the *) and the
problem should be fixed.

Updated README with Solaris dependencies

Added distro_shorthand to simplify lsb_release output

Added support for GuixSD

Add new `model` function to print device model name

Openwrt fixes