Added more error handling and necessary functions

icon.go

@@ -9,11 +9,11 @@ import (
 type Icon struct {
 	XMLName xml.Name `xml:"icon"`
 	*CommonAttributes
-	URI IRI `xml:",chardata"`
+	URI string `xml:",chardata"` // IRI
 }
 
 // NewIcon creates a new Icon. It returns a *Icon and an error.
-func NewIcon(uri IRI) (*Icon, error) {
+func NewIcon(uri string) (*Icon, error) {
 	if !isValidIRI(uri) {
 		return nil, fmt.Errorf("uri %v not correctly formatted", uri)
 	}