title: Error code one when trying to install python module
body: <p>after command pip install spotify-ripper</p>
  
  <pre><code>Command "/Users/ink/.pyenv/versions/2.7.10/bin/python2.7 -u -c "import     
  setuptools,
  tokenize;__file__='/private/var/folders/x4/6m1qwdmx7x9_qsbwv4zsny6w0000gn/T
  /pip-build-oQ_7kB/cffi/setup.py';exec(compile(getattr(tokenize, 'open',      
  open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" 
  install --record /var/folders/x4/6m1qwdmx7x9_qsbwv4zsny6w0000gn/T/pip-
  3YzrfM-record/install-record.txt --single-version-externally-managed --
  compile" failed with error code 1 in     
  /private/var/folders/x4/6m1qwdmx7x9_qsbwv4zsny6w0000gn/T/pip-build-
  oQ_7kB/cffi/
  </code></pre>
  
  <p>also this is pretty important</p>
  
  <pre><code>c/_cffi_backend.c:15:10: fatal error: 'ffi.h' file not found
  #include &lt;ffi.h&gt;
           ^
  1 error generated.
  error: command 'clang' failed with exit status 1
  </code></pre>