chore: 给bi.file加个setUrl方法

src/base/single/editor/editor.multifile.js

@@ -71,6 +71,10 @@ BI.MultifileEditor = BI.inherit(BI.Widget, {
         this.file.reset();
     },
 
+    setUrl: function (v) {
+        this.file.setUrl(v);
+    },
+
     setMaxFileLength: function (v) {
         this.file.setMaxFileLength(v);
     },

src/base/single/input/file.js

@@ -655,6 +655,13 @@
             });
         },
 
+        setUrl: function(v) {
+            this.options.url = v;
+            if (this.wrap) {
+                this.wrap.url = v;
+            }
+        },
+
         setMaxFileLength: function (v) {
             this.options.maxLength = v;
             if (this.wrap) {