Add modern Node.js to travis tests

Author: mariocasciaro

.travis.yml

@@ -1,8 +1,11 @@
 sudo: false
 language: node_js
 node_js:
-  - "0.12"
   - "0.10"
+  - "0.12"
   - "4"
   - "6"
+  - "8"
+  - "10"
+  - "14"
 after_script: NODE_ENV=test istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js && rm -rf ./coverage