Add multiple node versions

Author: tomdale

.travis.yml

@@ -1,5 +1,20 @@
 ---
 language: node_js
+node_js:
+  - "4.1"
+  - "4.0"
+  - "0.12"
+  - "0.11"
+  - "0.10"
+
+env:
+  - CXX=g++-4.8 WORKER_COUNT=2
+addons:
+  apt:
+    sources:
+      - ubuntu-toolchain-r-test
+    packages:
+      - g++-4.8
 
 sudo: false