Lab 19. Restricting a Type in another Namespace

Open country.xsd and examine it. It defines a 
type, country, in the namespace: http://www.country.org.

Open holiday.xsd and examine it. It defines a type,
country-visited-type, that restricts country.

You are to restrict country so that:
   - there is one <name> element
   - there is zero <population> element
   - there is one <capital> element
