Test against node v0.12 --> v4.2

- Test latest node and remove 0.10 and 0.11 and allow for failing tests against the latest unstable release, just for curiousity.

- Update jsdom to its latest version to support benchmarking on node 4+.

.travis.yml

@@ -1,9 +1,13 @@
 language: node_js
 node_js:
-  - "0.10"
-  - 0.11
+  - "stable"
+  - "unstable"
+  - "4.2"
+  - "4.1"
+  - "4"
+  - "0.12"
 script: make travis-test
 matrix:
   fast_finish: true
   allow_failures:
-    - node_js: 0.11
+    - node_js: "unstable"

package.json

@@ -32,12 +32,14 @@
     "coveralls": "~2.10",
     "expect.js": "~0.3.1",
     "istanbul": "~0.2",
-    "jsdom": "~0.8.9",
     "jshint": "~2.5.1",
     "mocha": "*",
     "xyz": "~0.5.0"
   },
   "scripts": {
     "test": "make test"
+  },
+  "optionalDependencies": {
+    "jsdom": "^7.0.2"
   }
 }