Add 4.3-4.6 and 6.4-6.8 to travis.yaml

Author: AJ Keller

.travis.yml

@@ -3,11 +3,20 @@ node_js:
   - "4.0"
   - "4.1"
   - "4.2"
+  - "4.3"
+  - "4.4"
+  - "4.5"
+  - "4.6"
   - "5.11.0"
   - "6.0"
   - "6.1"
   - "6.2"
   - "6.3"
+  - "6.4"
+  - "6.5"
+  - "6.6"
+  - "6.7"
+  - "6.8"
 install:
   - npm install --all
 script: