fix(onclosetag): notify virtual closing tags

fix isaacs#262:
Emit a boolean value to indicate if the onclosetag event was sent
without the closing tag actually existing in the document.

Also:
- changed the event emitters function to take a variable arguments list

lib/sax.js

@@ -621,13 +621,13 @@
   // shorthand
   S = sax.STATE
 
-  function emit (parser, event, data) {
-    parser[event] && parser[event](data)
+  function emit (parser, event, ...data) {
+    parser[event] && parser[event](...data)
   }
 
-  function emitNode (parser, nodeType, data) {
+  function emitNode (parser, nodeType, ...data) {
     if (parser.textNode) closeText(parser)
-    emit(parser, nodeType, data)
+    emit(parser, nodeType, ...data)
   }
 
   function closeText (parser) {
@@ -887,7 +887,7 @@
     while (s-- > t) {
       var tag = parser.tag = parser.tags.pop()
       parser.tagName = parser.tag.name
-      emitNode(parser, 'onclosetag', parser.tagName)
+      emitNode(parser, 'onclosetag', parser.tagName, s > t)
 
       var x = {}
       for (var i in tag.ns) {