Implement PairedQueue

Didn't have time tonight to get int priorities working in some cases

src/backing/item.rs

@@ -10,12 +10,12 @@ pub struct Item<D: Clone, P: PartialOrd + Clone> {
 
 impl<D: Clone, P: PartialOrd + Clone> Item<D, P> {
     /// Creates a new instance
-    fn new(data: D, priority: P) -> Self {
+    pub fn new(data: D, priority: P) -> Self {
         Self { data, priority }
     }
 
     /// Retrieve the internal data, it would be nicer to implement this using [`From`] or [`Into`], but I don't see a way to do that using generics
-    fn data(self) -> D {
+    pub fn data(self) -> D {
         self.data
     }
 }