ValueError in io.data Options get_all_data function. Could not convert string to float.
When making the request

```
opt = Options('PCLN', 'yahoo')
data = opt.get_all_data()
```

I get the error:

ValueError                                Traceback (most recent call last)
<ipython-input-8-f49f9e288226> in <module>()
      1 opt = Options('PCLN', 'yahoo')
----> 2 data = opt.get_all_data()

/usr/local/lib/python3.4/dist-packages/pandas/io/data.py in get_all_data(self, call, put)
   1088             expiry_dates, _ = self._get_expiry_dates_and_links()
   1089 
-> 1090         return self._get_data_in_date_range(dates=expiry_dates, call=call, put=put)
   1091 
   1092     def _get_data_in_date_range(self, dates, call=True, put=True):

/usr/local/lib/python3.4/dist-packages/pandas/io/data.py in _get_data_in_date_range(self, dates, call, put)
   1102                     frame = getattr(self, nam)
   1103                 except AttributeError:
-> 1104                     frame = self._get_option_data(expiry=expiry_date, name=name)
   1105                 data.append(frame)
   1106 

/usr/local/lib/python3.4/dist-packages/pandas/io/data.py in _get_option_data(self, expiry, name)
    721             frames = getattr(self, frame_name)
    722         except AttributeError:
--> 723             frames = self._get_option_frames_from_yahoo(expiry)
    724 
    725         option_data = frames[name]

/usr/local/lib/python3.4/dist-packages/pandas/io/data.py in _get_option_frames_from_yahoo(self, expiry)
    653     def _get_option_frames_from_yahoo(self, expiry):
    654         url = self._yahoo_url_from_expiry(expiry)
--> 655         option_frames = self._option_frames_from_url(url)
    656         frame_name = '_frames' + self._expiry_to_string(expiry)
    657         setattr(self, frame_name, option_frames)

/usr/local/lib/python3.4/dist-packages/pandas/io/data.py in _option_frames_from_url(self, url)
    682         if not hasattr(self, 'underlying_price'):
    683             try:
--> 684                 self.underlying_price, self.quote_time = self._get_underlying_price(url)
    685             except IndexError:
    686                 self.underlying_price, self.quote_time = np.nan, np.nan

/usr/local/lib/python3.4/dist-packages/pandas/io/data.py in _get_underlying_price(self, url)
    700         root = self._parse_url(url)
    701         underlying_price = float(root.xpath('.//*[@class="time_rtq_ticker Fz-30 Fw-b"]')[0]\
--> 702             .getchildren()[0].text)
    703 
    704         #Gets the time of the quote, note this is actually the time of the underlying price.

ValueError: could not convert string to float: '1,044.60'

It looks like commas just need to be stripped from the text before converting to a float.
