Fix build (#19)

* Update node version

* Patch up BrowserStack keys

Author: Jonny Reeves

.nvmrc

@@ -0,0 +1 @@
+v8.9.4

.travis.yml

@@ -1,12 +1,10 @@
 language: node_js
-node_js:
-  - "4"
 cache:
   directories:
     - node_modules
 before_install:
   - true && `base64 --decode <<< ZXhwb3J0IEJST1dTRVJfU1RBQ0tfVVNFUk5BTUU9aW1wcm9iYWJsZWVuZ2JvdDEK`
-  - true && `base64 --decode <<< ZXhwb3J0IEJST1dTRVJfU1RBQ0tfQUNDRVNTX0tFWT1xTGJxUjE2azhqdFducVh2RmlvZwo=`
+  - true && `base64 --decode <<< ZXhwb3J0IEJST1dTRVJfU1RBQ0tfQUNDRVNTX0tFWT1SRG1Cc2pwQUJ4RlljcEVkeVp5bwo=`
 install: npm install
 script:
-  - npm run test
+  - npm run test