Maps are missing several countries

[leecbaker]

Pygal's maps module seems to have an interesting ad-hoc selection of countries represented on the map. I've found several that are missing:

• Qatar
• Grenada
• Saint Kitts and Nevis
• Saint Lucia
• Barbados
• Federated States of Micronesia
• Bahamas
• Trinidad and Tobago

Ideally pygal should support rendering the standard list of countries from ISO 3166, and use the country abbreviations standardized in ISO3166-1 alpha-2.

[a455bcd9]

Other missing countries:

• South Sudan (and the map of Sudan itself is therefore wrong)
• the Isle of Man

[a455bcd9]

@leecbaker I updated the world map with all iso codes, you can find it here: https://github.com/Kozea/pygal_maps_world/pull/5