* add option `theme` that allows for setting of a theme,
the default is `default`
* under `themes` the themes can be described as follows:
either:
```
themes:
default:
fg: [0,0,0]
bg: [0,0,0]
black: [0,0,0]
red: [0,0,0]
green: [0,0,0]
yellow: [0,0,0]
blue: [0,0,0]
magenta: [0,0,0]
cyan: [0,0,0]
white: [0,0,0]
orange: [0,0,0]
```
or
```
themes:
default:
fg: 0
bg: 0
black: 0
red: 0
green: 0
yellow: 0
blue: 0
magenta: 0
cyan: 0
white: 0
orange: 0
```
If the key is different from default, it needs to either be specified on
start with `options --theme [THEME]`, or in the configuration file under
theme: [THEME].
closes#390
ce73b6cca0