Changes to avoid issues with normalizing a phone number started with reserved +0 country code.

We've faced an issue with normalizing a test phone number that starts with reserved +0 country code. The issue was with normalize() method that returned '0' as a normalized phone number when we used "+00 000 000 000" number in our test cases. It's not a big dial to use another test number but from my point of view such wrong numbers should have not be recognized as a valid # as +0 zone is not assigned to a country.  
Based on the fact that E.164 does not use that zone and there is no plans to include it to this standard I suggest to get rid of it and that's why I am sending this pull request.
But just in case I've only commented this part out to be able to return it back in the future if they assign this code to a country(but I believe it will not be a the nearest future because of bureaucracy) And anyway it will be better to add this zone and an appropriate number format for it only when and if it happens.