Expand API support, including some V2 endpoints (#4)

Switch to V2 versions of some APIs:

* place order
* cancel order

Add missing APIs:

* cancel all orders
* replace order
* get symbols

Add support for custom order ID for cancel active order.

lib/rest-client.js

@@ -19,7 +19,7 @@ module.exports = class RestClient {
 
     if(params.order_type === 'Limit') assert(params.price, 'Parameter price is required for limit orders');
 
-    return await this.request.post('/open-api/order/create', params);
+    return await this.request.post('/v2/private/order/create', params);
   }
 
   async getActiveOrder(params) {
@@ -28,9 +28,24 @@ module.exports = class RestClient {
 
   async cancelActiveOrder(params) {
     assert(params, 'No params passed');
-    assert(params.order_id, 'Parameter order_id is required');
+    assert(params.order_id || params.order_link_id, 'Parameter order_id OR order_link_id is required');
 
-    return await this.request.post('/open-api/order/cancel', params);
+    return await this.request.post('/v2/private/order/cancel', params);
+  }
+
+  async cancelAllActiveOrders(params) {
+    assert(params, 'No params passed');
+    assert(params.symbol, 'Parameter symbol is required');
+
+    return await this.request.post('/v2/private/order/cancelAll', params);
+  }
+
+  async replaceActiveOrder(params) {
+    assert(params, 'No params passed');
+    assert(params.order_id || params.order_link_id, 'Parameter order_id OR order_link_id is required');
+    assert(params.symbol, 'Parameter symbol is required');
+
+    return await this.request.post('/open-api/order/replace', params);
   }
 
   async placeConditionalOrder(params) {
@@ -126,6 +141,10 @@ module.exports = class RestClient {
     return await this.request.get('/v2/public/time');
   }
 
+  async getSymbols() {
+    return await this.request.get('/v2/public/symbols');
+  }
+
   async getTimeOffset() {
     return await this.request.getTimeOffset();
   }