Merge pull request sintaxi#65 from zachahn/master

fix issue sintaxi#64

lib/helpers.js

@@ -5,7 +5,7 @@ var qs    = require("querystring")
 module.exports = function(config){
   var root    = config.root || "sandbox"
   var signer  = oauth(config.app_key, config.app_secret)
-  var scope   = config.scope
+  var scope   = config.scope = config.scope || ""
 
   return {  
     sign: function(token, args){
@@ -111,13 +111,13 @@ module.exports = function(config){
       var fileop   = obj.action.split("/")[0] == "fileops"
 
       // fileops calls desn't want root in path
-      var rootpath = fileop ? null : root
+      var rootpath = fileop ? "" : root
 
       // fileops calls desn't want scope in path
-      var scopepath = fileop ? null : scope
+      var scopepath = fileop ? "" : scope
 
       // we wont always have this
-      var filepath = obj.path ? qs.escape(obj.path) : null
+      var filepath = obj.path ? qs.escape(obj.path) : ""
 
       // build full path
       var fullpath = path.join(obj.hostname)