Change xmldom dependency from master to release tag (#66)

* Updated the xmldom dependency to use a tag instead of pointing at master.

* 3.3.3

* Updating the Node4 version for the Travis CI job

.travis.yml

@@ -1,7 +1,7 @@
 sudo: false
 language: node_js
 node_js:
-  - 4.4.7
+  - 4.8.5
   - 6.9.2
 before_install:
   - npm i -g npm@latest

package.json

@@ -1,6 +1,6 @@
 {
   "name": "samlp",
-  "version": "3.3.2",
+  "version": "3.3.3",
   "description": "SAML Protocol server middleware",
   "main": "lib/index.js",
   "scripts": {
@@ -25,7 +25,7 @@
     "saml": "^0.12.1",
     "thumbprint": "0.0.1",
     "xml-crypto": "^0.10.1",
-    "xmldom": "https://github.com/auth0/xmldom/tarball/master",
+    "xmldom": "auth0/xmldom#v0.1.19-auth0_1",
     "xpath": "0.0.5",
     "xtend": "^1.0.3"
   },