fix pull request 6

Author: maxgalbu

coffee/assertions/jqueryElementNotPresent.coffee

@@ -23,6 +23,7 @@ exports.assertion = (selector, msg) ->
 		return !value;
 
 	this.value = (result) ->
+		return false if !result;
 		return result.value;
 
 	this.command = (callback) ->

js/assertions/jqueryElementNotPresent.js

@@ -24,6 +24,9 @@ exports.assertion = function(selector, msg) {
     return !value;
   };
   this.value = function(result) {
+    if (!result) {
+      return false;
+    }
     return result.value;
   };
   this.command = function(callback) {