Improve error message

Signed-off-by: Fabio José <fabiojose@gmail.com>

lib/specs/spec_0_2.js

@@ -36,7 +36,7 @@ Spec02.prototype.check = function(){
   var valid = validate(this.payload);
 
   if(!valid) {
-    throw {message: "invalid payload"};
+    throw {message: "invalid payload", errors: validate.errors};
   }
 
 };