Build: Add Node 6.x to Travis (fixes #99) (#98)

Author: dannyfritz

.travis.yml

@@ -1,7 +1,11 @@
-language: node_js
-sudo: false
-node_js:
-    - "0.12"
-    - 4
-after_success:
-    - npm run coveralls
+language: node_js
+sudo: false
+node_js:
+    - "0.12"
+    - 4
+    - 6
+before_script:
+    - npm install -g npm-install-peers
+    - npm-install-peers
+after_success:
+    - npm run coveralls