Drop iojs supports and add last node version to the CI matrix

Author: armandabric

.travis.yml

@@ -3,9 +3,16 @@ language: node_js
 sudo: false
 
 node_js:
-    - "iojs-v2.4.0"
-    - "iojs-v3.1.0"
-    - "iojs-v3.2.0"
+    - "5.7"
+    - "5.6"
+    - "5.5"
+    - "5.4"
+    - "5.3"
+    - "5.2"
+    - "5.1"
+    - "5.0"
+    - "4.3"
+    - "4.2"
     - "0.12"
 
 script: