Adding support for core Unix commands and common package managers

[fusion809]

Hi,

In this pull request I am adding support to this package for core Unix commands (e.g., cp, dd and sudo) and common package managers, while also making some minor amendments to the package.json's metadata. This involved adding some extra Less styles which are not supported by most themes. If it helps, here are some example values for these styles:

.source.shell {
  .support.function.coreutils {
    color: rgb(150,255,150);
  }

  .support.function.extras {
    color: rgb(255,150,200);
  }

  .support.function.packages {
    color: rgb(255,220,120);
  }
}

Thanks for your time,
Brenton