Light/dark theme switching

Unfortunately, this package doesn't support the built-in light/dark mode switching with:

```json
{
  "light_color_scheme": "Packages/User/BetterFindBuffer-Light.hidden-tmTheme",
  "dark_color_scheme": "Packages/User/BetterFindBuffer-Dark.hidden-tmTheme",
}
```

It only accepts `color_scheme`. Any ideas how to add this or is it quite involved to integrate?