title: syntastic with python no warnings and error arrows
body: <p>I have following <a href="https://github.com/mictadlo/vimrc4GO/blob/master/.vimrc" rel="nofollow noreferrer">vimrc</a>, but I do not get arrows for warnings and error from syntastic<img src="https://i.stack.imgur.com/bQzLZ.png" alt=""> </p>
  
  <p>like on the picture below <img src="https://i.stack.imgur.com/nMc9l.png" alt="enter image description here"></p>
  
  <p>Further more I am not able to use the ruler with <strong>set ruler</strong>. Why I do not get a warning that variable "a" is not used? </p>
  
  <p>What did I do wrong?</p>
  
  <p>Thank you in advance.</p>