Updated deps, replaced yarn with npm@5

Author: ctrlplusb

.travis.yml

@@ -1,16 +1,16 @@
 sudo: false
 language: node_js
 cache:
-  yarn: true
+  npm: true
   directories:
     - node_modules
 node_js:
 - '6'
 script:
 # Unfortunately flow falls over when a dep exists in peer deps and others. :(
 # @see https://github.com/flowtype/flow-typed/issues/528
-#- yarn run flow:defs
-- yarn run check
+#- npm run flow:defs
+- npm run check
 after_success:
 # Deploy code coverage report to codecov.io
-- yarn run test:coverage:deploy
+- npm run test:coverage:deploy