Merge pull request #49 from lewisf/fix-screenboard-create-callback-detect

An argument was removed so the detection should be changed

lib/api/screenboard.js

@@ -58,7 +58,7 @@ var util = require("util");
  *  ```
  */
 function create(boardTitle, widgets, options, callback){
-    if(arguments.length < 5 && typeof arguments[3] === "function"){
+    if(arguments.length < 4 && typeof arguments[2] === "function"){
         callback = options;
         options = {};
     }