Terminal colors not supported

Both source files `colors/codedark.vim` and `autoload/airline/themes/codedark.vim` are prepared for terminal colors. All colors are defined as dictionary variables, e.g.

```
let s:cdBlue = {'gui': '#569CD6', 'cterm': '00'}
let s:cdLightBlue = {'gui': '#9CDCFE', 'cterm': '00'}
```

What is missing are correct `cterm` colors in those variables.
