Extractor value error from call as per README

[martindisley]

Hey Jordi

When I run extractor as per the readme:
taggram, tags = extractor(<path>, model='MTT_musicnn')
I get a value error:
File "<stdin>", line 1, in <module> ValueError: too many values to unpack (expected 2)

works fine if run it as per the tagging_example.ipynb:
taggram, tags = extractor(<path>, model='MTT_musicnn', extract_features=False)

Error:

>>> taggram, tags = extractor('Bounce08.wav', model='MTT_musicnn')
Computing spectrogram (w/ librosa) and tags (w/ tensorflow).. done!
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: too many values to unpack (expected 2)
>>> taggram, tags = extractor('Bounce08.wav', model='MTT_musicnn', extract_features=False)
Computing spectrogram (w/ librosa) and tags (w/ tensorflow).. done!
>>>

Edit: installed with PyPi