Handle US (?) 1-800 numbers

[peterfig]

phone_country(18006539867)

---------------------------------------------------------------------------
InvalidPhone                              Traceback (most recent call last)
<ipython-input-40-2373d1fa8ebf> in <module>()
----> 1 phone_country(18006539867)

/Users/peter/Virtualenvs/standard2/lib/python2.7/site-packages/phone_iso3166/country.pyc in phone_country(phone)
     17                 return m
     18     except:
---> 19         raise InvalidPhone('Invalid phone {}'.format(phone))
     20 
     21 

InvalidPhone: Invalid phone 18006539867