chore: remove NODE 4 from Travis.

Author: hansl

.travis.yml

@@ -1,15 +1,14 @@
 sudo: false
 env:
-  - NODE_VERSION=4 SCRIPT=lint
-  - NODE_VERSION=4 SCRIPT=test
+  - NODE_VERSION=5 SCRIPT=lint
   - NODE_VERSION=5 SCRIPT=test
 os:
   - linux
   - osx
 matrix:
   exclude:
     - os: osx
-      env: NODE_VERSION=4 SCRIPT=lint
+      env: NODE_VERSION=5 SCRIPT=lint
 
 script:
   - npm run-script $SCRIPT