Drop support for old non LTS node versions

Author: Souler

.travis.yml

@@ -2,14 +2,9 @@ language: node_js
 env:
   - NODE_ENV=test
 node_js:
-  - "0.10"
-  - "0.12"
-  - "1.8"
-  - "2.5"
-  - "3.3"
-  - "4.4"
-  - "5.11"
-  - "6.2"
+  - 4
+  - 5
+  - 6
 sudo: false
 cache:
   directories:

package.json

@@ -63,6 +63,9 @@
     "should": "^11.1.0",
     "sinon": "^1.17.5"
   },
+  "engines": {
+    "node": ">=4"
+  },
   "nyc": {
     "sourceMap": false,
     "instrument": false