Update compatibility with Node.js lastest and LTS

Author: timonreinhard

.travis.yml

@@ -2,9 +2,7 @@ env:
   - npm_config_coverage=true
 language: node_js
 node_js:
-  - "5"
-  - "4.1"
-  - "4.0"
-  - "0.12"
+  - "6"
+  - "8"
 after_success:
   - bash <(curl -s https://codecov.io/bash)

package.json

@@ -44,5 +44,8 @@
     "mitm": "^1.3.2",
     "mocha": "^3.5.0",
     "must": "^0.13.4"
+  },
+  "engines": {
+    "node": ">=6"
   }
 }