Method getPlaylists

* get full playlist objects, including tracks, for passed in array of playlistId * @param limit max # of items to return * @param offset offset into list to return from (for pagination) * @param idsArray list of playlist ids * @param targetUserId the user whose playlists we're trying to

(
    limit = 100,
    offset = 0,
    idsArray = null,
    targetUserId = null,
    withUsers = false
  )