Fixes to the typings so that they are used better

i18next-xhr-backend/i18next-xhr-backend.d.ts

@@ -1,5 +1,5 @@
 // Type definitions for i18next-xhr-backend 1.2.0
-// Project: http://i18next.com/
+// Project: https://github.com/i18next/i18next-xhr-backend
 // Definitions by: Jan Mühlemann <https://github.com/jamuhl>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
@@ -12,23 +12,25 @@ declare module 'i18next-xhr-backend' {
         interpolator: Interpolator
     }
 
+    interface BackendOptions {
+        loadPath: string | Function,
+        addPath:  string,
+        allowMultiLoading: boolean,
+        parse: Function,
+        crossDomain: boolean,
+        withCredentials: boolean,
+        ajax: Function
+    }
+
     export default class Backend {
         type: 'backend';
         services: Services;
-        options: {
-            loadPath: string | Function,
-            addPath:  string,
-            allowMultiLoading: boolean,
-            parse: () => {},
-            crossDomain: boolean,
-            withCredentials: boolean,
-            ajax: () => void
-        };
-        constructor(services: Services, options?: {});
-        init(services: Services, options?: {}): void;
-        readMulti(languages: any[], namespaces: any[], callback: () => void): void;
-        read(language: {}, namespace: {}, callback: () => void): void;
-        loadUrl(url: string, callback: () => void): void;
+        options: BackendOptions;
+        constructor(services: Services, options?: BackendOptions);
+        init(services: Services, options?: BackendOptions): void;
+        readMulti(languages: any[], namespaces: any[], callback: Function): void;
+        read(language: {}, namespace: {}, callback: Function): void;
+        loadUrl(url: string, callback: Function): void;
         create(languages: any[], namespace: string, key: string, fallbackValue: string): void;
     }
 }