Node version (or tell us if you're using electron or some other framework):

v6.4.0

ShellJS version (the most recent version/Github branch you see the bug on):

0.7.5

Operating system:

Mac OS Yosemite

Description of the bug:

Getting option not recognized when running ls -d

Example ShellJS command to reproduce the error:

var shell = require("shelljs");

shell.ls("-d", "./").forEach(function(dir){
    if(dir !== "node_modules"){
      console.log("dir: " + dir);
    }
  });