added connection selector to listen node

nodes/xilica-listen.html

@@ -4,6 +4,7 @@ RED.nodes.registerType('xilica-listen', {
   color: '#dddddd',
   defaults: {
     name: { value: "" },
+    connection: { value: "", type: "xilica-connection" },
     rules: { value: [] }
   },
   inputs: 1,
@@ -117,6 +118,10 @@ RED.nodes.registerType('xilica-listen', {
     <label for="node-input-name">Name</label>
     <input type="text" id="node-input-name">
   </div>
+  <div class="form-row">
+    <label for="node-input-connection">Connection</label>
+    <input type="text" id="node-input-connection">
+  </div>
   <div class="form-row">
     <label>Rules</label>
     <ol id="node-input-rules"></ol>