Revert "Empty strings now returns error cause its not valid XML"

This reverts commit b9b44e0.

package.json

@@ -6,7 +6,7 @@
     "json"
   ],
   "homepage": "https://github.com/Leonidas-from-XIV/node-xml2js",
-  "version": "0.4.18",
+  "version": "0.4.19",
   "author": "Marek Kubica <[email protected]> (https://xivilization.net)",
   "contributors": [
     "maqr <[email protected]> (https://github.com/maqr)",

src/parser.coffee

@@ -237,8 +237,8 @@ class exports.Parser extends events.EventEmitter
     try
       str = str.toString()
       if str.trim() is ''
-        @emit 'error', new Error "Empty string is not valid XML"
-        return
+        @emit "end", null
+        return true
 
       str = bom.stripBOM str
       if @options.async

test/parser.test.coffee

@@ -254,11 +254,8 @@ module.exports =
   'test empty tag result specified null': skeleton(emptyTag: null, (r) ->
     equ r.sample.emptytest[0], null)
 
-  'test invalid empty XML file': (test) ->
-    x2js = new xml2js.Parser()
-    x2js.parseString '', (err, r) ->
-      assert.notEqual err, null
-      test.finish()
+  'test invalid empty XML file': skeleton(__xmlString: ' ', (r) ->
+    equ r, null)
 
   'test enabled normalizeTags': skeleton(normalizeTags: true, (r) ->
     console.log 'Result object: ' + util.inspect r, false, 10