title: Error in opencv 3.1.0 using SURF
body: <p>I am new to opencv and using version 3.1.0 . I am trying to build a simple tutorial from this link : <a href="http://docs.opencv.org/3.1.0/d7/d66/tutorial_feature_detection.html#gsc.tab=0" rel="nofollow">http://docs.opencv.org/3.1.0/d7/d66/tutorial_feature_detection.html#gsc.tab=0</a> </p>
  
  <p>But an error occurs :  opencv2/xfeatures2d.hpp: No such file or directory </p>
  
  <p>How is that possible ? Can you help me ? </p>