Added more error handling and necessary functions

logo.go

@@ -8,11 +8,11 @@ import (
 type Logo struct {
 	XMLName xml.Name `xml:"logo"`
 	*CommonAttributes
-	URI IRI `xml:",chardata"`
+	URI string `xml:",chardata"` // IRI
 }
 
-// NewLogo creates a new Logo. It returns a *Logo.
-func NewLogo(uri IRI) (*Logo, error) {
+// NewLogo creates a new Logo. It returns a *Logo and an error.
+func NewLogo(uri string) (*Logo, error) {
 	if !isValidIRI(uri) {
 		return nil, fmt.Errorf("uri %v not correctly formatted", uri)
 	}