Update nodejs version in travis (#73)

* Update nodejs versions  in travis, close #72

* Remove minor versions from travis, use only major

Author: s0ph1e

.travis.yml

@@ -1,14 +1,13 @@
 language: node_js
 sudo: false
 node_js:
-  - "5.1"
-  - "4.2"
-  - "4.1"
-  - "4.0"
-  - "0.12"
-  - "0.11"
   - "0.10"
+  - "0.11"
+  - "0.12"
   - "iojs"
+  - "4"
+  - "5"
+  - "6"
 after_success:
   - codeclimate-test-reporter < coverage/lcov.info
   - coveralls < coverage/lcov.info