deprecate http.cat

lib/http.js

@@ -1628,6 +1628,8 @@ exports.cat = function(url, encoding_, headers_) {
       headers = {},
       callback = null;
 
+  console.error("http.cat will be removed in the near future. use http.get");
+
   // parse the arguments for the various options... very ugly
   if (typeof(arguments[1]) == 'string') {
     encoding = arguments[1];