Test Node v10 and remove EOL releases

Author: jakezatecky

.travis.yml

@@ -1,9 +1,9 @@
 language: node_js
 node_js:
   - '6'
-  - '7'
   - '8'
   - '9'
+  - '10'
 before_script:
   # Remove ./node_modules/.bin from PATH so node-which doesn't replace Unix which and cause RVM to barf. See https://github.com/travis-ci/travis-ci/issues/5092
   - PATH=${PATH//:\.\/node_modules\/\.bin/}