Add tag support to v09 assembleEvent

Any metric prepended with __t__ will be viewed as a tag

lib/influxdb.js

@@ -393,13 +393,34 @@ InfluxdbBackend.prototype.assembleEvent_v08 = function (name, events) {
 
 InfluxdbBackend.prototype.assembleEvent_v09 = function (name, events) {
   var self = this;
+  var tag_symbol = "__t__";
+  var measurement_pieces = [];
+  var tags = {};
+  var pieces = name.split(".");
+
+  var i = 0;
+  while (i < pieces.length) {
+    if (pieces[i].substr(0,tag_symbol.length) == tag_symbol) {
+       var tag = pieces[i].substr(tag_symbol.length);
+       tags[tag] = pieces[i+1];
+       i += 2;
+    }
+    else {
+       measurement_pieces.push(pieces[i]);
+       i++;
+    }
+  }
+
+  var measurement = measurement_pieces.join(".");
 
   var payload = {
-    measurement: name,
-    fields: { value: events[0]['value'] }
+    measurement: measurement,
+    fields: { value: events[0]['value'] },
+    tags: tags
   }
 
   return payload;
+
 }
 
 InfluxdbBackend.prototype.httpPOST_v08 = function (points) {