text: Title: Example Code Doesn't Work in Python 3.6.1
  Body: Installed alpha_vantage from pip.
  
  `from alpha_vantage.timeseries import TimeSeries
  import matplotlib.pyplot as plt
  
  ts = TimeSeries(key='my key was here', output_format='pandas')
  data, meta_data = ts.get_intraday(symbol='MSFT',interval='1min', outputsize='full')
  data['close'].plot()
  plt.title('Intraday Times Series for the MSFT stock (1 min)')
  plt.show()`
  
  "C:\Users\Doug\OneDrive\family\doug\work in progress\alphavantage\alphaenv\Scripts\python.exe" "C:/Users/Doug/OneDrive/family/doug/work in progress/alphavantage/rolling returns/alpha_play.py"
  Traceback (most recent call last):
    File "C:\Users\Doug\OneDrive\family\doug\work in progress\alphavantage\alphaenv\lib\site-packages\pandas\core\indexes\base.py", line 2525, in get_loc
      return self._engine.get_loc(key)
    File "pandas\_libs\index.pyx", line 117, in pandas._libs.index.IndexEngine.get_loc
    File "pandas\_libs\index.pyx", line 139, in pandas._libs.index.IndexEngine.get_loc
    File "pandas\_libs\hashtable_class_helper.pxi", line 1265, in pandas._libs.hashtable.PyObjectHashTable.get_item
    File "pandas\_libs\hashtable_class_helper.pxi", line 1273, in pandas._libs.hashtable.PyObjectHashTable.get_item
  KeyError: 'close'
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "C:/Users/Doug/OneDrive/family/doug/work in progress/alphavantage/rolling returns/alpha_play.py", line 6, in <module>
      data['close'].plot()
    File "C:\Users\Doug\OneDrive\family\doug\work in progress\alphavantage\alphaenv\lib\site-packages\pandas\core\frame.py", line 2139, in __getitem__
      return self._getitem_column(key)
    File "C:\Users\Doug\OneDrive\family\doug\work in progress\alphavantage\alphaenv\lib\site-packages\pandas\core\frame.py", line 2146, in _getitem_column
      return self._get_item_cache(key)
    File "C:\Users\Doug\OneDrive\family\doug\work in progress\alphavantage\alphaenv\lib\site-packages\pandas\core\generic.py", line 1842, in _get_item_cache
      values = self._data.get(item)
    File "C:\Users\Doug\OneDrive\family\doug\work in progress\alphavantage\alphaenv\lib\site-packages\pandas\core\internals.py", line 3843, in get
      loc = self.items.get_loc(item)
    File "C:\Users\Doug\OneDrive\family\doug\work in progress\alphavantage\alphaenv\lib\site-packages\pandas\core\indexes\base.py", line 2527, in get_loc
      return self._engine.get_loc(self._maybe_cast_indexer(key))
    File "pandas\_libs\index.pyx", line 117, in pandas._libs.index.IndexEngine.get_loc
    File "pandas\_libs\index.pyx", line 139, in pandas._libs.index.IndexEngine.get_loc
    File "pandas\_libs\hashtable_class_helper.pxi", line 1265, in pandas._libs.hashtable.PyObjectHashTable.get_item
    File "pandas\_libs\hashtable_class_helper.pxi", line 1273, in pandas._libs.hashtable.PyObjectHashTable.get_item
  KeyError: 'close'
  
  Process finished with exit code 1
  
  