getDesignName = (fs, paths) => {
  if (!paths) {
    return 'undefined'
  }
  const mainPath = toArray(paths)[0]
  const stats = fs.statSync(mainPath)
  if (stats.isFile()) { // if main path is a file, find its folder
    const dirName = path.dirname(mainPath)
    return packageNameFromDir(fs, dirName, mainPath)
  } else if (stats.isDirectory()) { // if main path is a folder , try to find name from package.json
    // try to use package.json & co to find main
    return packageNameFromDir(fs, mainPath)
  }
}
extract the design name from
@param  {Object} fs a file-system like object (either node's fs or some other) providing at least statSync, existSync, readFileSync
@param  {Array} paths an array of paths (strings) or a single path