Added and corrected comments

person.go

@@ -14,11 +14,12 @@ type Person struct {
 	Extensions []*ExtensionElement `xml:",any,omitempty"`
 }
 
+// NewPerson creates a new Person. It returns a *Person.
 func NewPerson(name string) *Person {
 	return &Person{Name: name}
 }
 
-// AddExtension adds the extension to the person
+// AddExtension adds the Extension to the Person.
 func (p *Person) AddExtension(e *ExtensionElement) {
 	if p.Extensions == nil {
 		p.Extensions = make([]*ExtensionElement, 1)
@@ -28,6 +29,8 @@ func (p *Person) AddExtension(e *ExtensionElement) {
 	}
 }
 
+// Check checks the Person for incompatibilities with RFC4287. It returns an
+// error.
 func (p *Person) Check() error {
 	if p.Name == "" {
 		return errors.New("name element of person element empty")