Add Deluge widget

- Create semi-generic jsonrpc proxy handler
- Refactor NZBGet to use jsonrpc proxy handler

closes #190

src/widgets/deluge/widget.js

@@ -0,0 +1,8 @@
+import delugeProxyHandler from "./proxy";
+
+const widget = {
+  api: "{url}/json",
+  proxyHandler: delugeProxyHandler,
+};
+
+export default widget;