Add IntoUrl trait for Link type

With this we can translate a Link type into an URL type from url::Url

libimagbookmark/src/link.rs

@@ -1,5 +1,9 @@
 use std::ops::{Deref, DerefMut};
 
+use result::Result;
+
+use url::Url;
+
 #[derive(Debug, Clone)]
 pub struct Link(String);
 
@@ -19,3 +23,19 @@ impl DerefMut for Link {
     }
 
 }
+
+pub trait IntoUrl {
+    fn into_url(self) -> Result<Url>;
+}
+
+impl IntoUrl for Link {
+
+    fn into_url(self) -> Result<Url> {
+        use error::BookmarkErrorKind as BEK;
+        use error::MapErrInto;
+
+        Url::parse(&self[..]).map_err_into(BEK::LinkParsingError)
+    }
+
+}
+