title: opencv-python imshow giving errors in mac
body: <p>I installed opencv-python using pip install, in mac os. Now the cv2.imshow function giving following error</p>
  
  <blockquote>
    <p>OpenCV Error: Unspecified error (The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script) in cvShowImage</p>
  </blockquote>
  
  <p>How can I solve this issue? Why doesn't the pip check opencv dependencies?</p>