Log Message:
py-stdnum: updated to 1.20

changes from 1.19 to 1.20

* Add modules for the following number formats:
  - BC PHN (British Columbia Personal Health Number) (thanks Ömer Boratav)
  - EC Number (European Community number) (thanks Daniel Weber)
  - VID (Indian personal virtual identity number) (thanks Atul Deolekar)

* Fix typo in German Umsatzsteur Identifikationnummer (thanks Александр \ 
Кизеев)
* Ensure EU VAT numbers don't accept duplicate country codes
* Fix vatin number compacting for "EU" VAT numbers (thanks Davide Walder)
* Add check digit validation to French NIF (thanks Kevin Dagostino)
* Fix Ukrainian EDRPOU check digit calculation (thanks sector119)