add load order and access order url methods

src/acc/mod.rs

@@ -140,6 +140,18 @@ impl<P: Persist> Account<P> {
         Ok(NewOrder { order })
     }
 
+
+    /// Load an existing order from its URL.
+    ///
+    /// This can be used to resume processing of an order that was
+    /// created earlier.
+    pub fn load_order(&self, order_url: &str) -> Result<NewOrder<P>> {
+        let res = self.inner.transport.call(order_url, "")?;
+        let api_order: ApiOrder = read_json(res)?;
+        let order = Order::new(&self.inner, api_order, order_url.to_string());
+        Ok(NewOrder { order })
+    }
+
     /// Revoke a certificate for the reason given.
     ///
     /// This calls the ACME API revoke endpoint, but does not affect the locally persisted

src/order/mod.rs

@@ -170,6 +170,12 @@ impl<P: Persist> NewOrder<P> {
     pub fn api_order(&self) -> &ApiOrder {
         &self.order.api_order
     }
+
+
+    /// Access the order url 
+    pub fn order_url(&self) -> String {
+        self.order.url.clone()
+    }
 }
 
 /// An order that is ready for a [CSR] submission.