http request node add transport validity check and warn.

nodes/core/io/21-httprequest.html

@@ -103,7 +103,7 @@
             name: {value:""},
             method:{value:"GET"},
             ret: {value:"txt"},
-            url:{value:""},
+            url:{value:"",validate:function(v) { return (v.trim().length === 0) || (v.indexOf("://") === -1) || (v.trim().indexOf("http") === 0)} },
             tls: {type:"tls-config",required: false}
         },
         credentials: {
@@ -112,6 +112,9 @@
         },
         inputs:1,
         outputs:1,
+        outputLabels: function(i) {
+            return ({txt:"UTF8 string", bin:"binary buffer", obj:"parsed JSON object"}[this.ret]);
+        },
         icon: "white-globe.png",
         label: function() {
             return this.name||this._("httpin.httpreq");