title: How to encode url parameters in golang?
body: <p>Is there any go package to encode url?I need to encode a parameter(type in map[string]interface{}) before it was transfered in url.</p>
  
  <p>Maybe the parameter likes:<code>map[string]interface{}{"app_id":"you_api","app_sign":"md5_base_16","timestamp":"1473655478000"}
  </code>
  How to encode it and what the encoded result would be?</p>