update travis config to fix all warnings

Author: mreinstein

.travis.yml

@@ -1,4 +1,5 @@
-sudo: false
+dist: xenial
+os: linux
 language: node_js
 node_js:
 - '6'
@@ -14,7 +15,7 @@ env:
   - secure: r/aJSYB54gC/KDePoPyJFmhx2EzvJWUUnxOsYXY9jsFqWr+wHSlqXRXKrZ9MxNOvBD5+i6cpQBjICUo3OEJGaNE3i27xg9FN2mHGUaooUzhnyLssSlcaomTrOex0fZ7S1HXy2kJL9FHNgAVEzUSbTgPVwFH8gzxvgK0hmgdOOX0=
   - secure: c0i4+3E5WqtKeT5X5C/DvwGq6s5gANuCwTudinT13Bk6lrGRiSTEEcrcR82HJytUnTTg5mywvQtayvaub55IBQlWbZhk0TxgZK9FZYGwJqmSO1gXpBMXe+8ybTnseUNCizZ7Lk+O1F1oYYL4YlJMn8LZ1JaAvZxwong7nNPV2bM=
 
-matrix:
+jobs:
   include:
   - node_js: '6'
     env: BROWSER_NAME=chrome BROWSER_VERSION=latest