[REST] Update API docs to add Get Order Transaction

- Updates Payments API
- Adds a new response object `Order Change` to describe changes to
  orders in the order book
- Update all source code URLs to permalinks
-

js/apitool-rest.js

@@ -237,7 +237,7 @@ Request("Cancel Order", {
 Request("Get Account Orders", {
     method: GET,
     path: "/v1/accounts/{:address}/orders?{:query_params}",
-    description: "Check the status of one or more orders attached to an account.",
+    description: "Get open currency-exchange orders associated with the Ripple address.",
     link: "#get-account-orders",
     params: {
         "{:address}": DEFAULT_ADDRESS_3,
@@ -245,6 +245,17 @@ Request("Get Account Orders", {
     }
 });
 
+Request("Get Order Transaction", {
+    method: GET,
+    path: "/v1/accounts/{:address}/orders/{:hash}",
+    description: "Get the details of an order transaction.",
+    link: "#get-order-transaction",
+    params: {
+        "{:address}": "rEQWVz1qN4DWw5J17s3DgXQzUuVYDSpK6M",
+        "{:hash}": "D53A3B99AC0C3CAF35D72178390ACA94CD42479A98CEA438EEAFF338E5FEB76D"
+    }
+});
+
 Request("Get Order Book", {
     method: GET,
     path: "/v1/accounts/{:address}/order_book/{:base}/{:counter}?{:query_params}",

rest-api-tool.html

@@ -99,6 +99,7 @@
                 <li>Place Order</li>
                 <li>Cancel Order</li>
                 <li>Get Account Orders</li>
+                <li>Get Order Transaction</li>
                 <li>Get Order Book</li>
                 <br/>
                 <li>Get Trustlines</li>