add go 1.6 to travis
diff --git a/.travis.yml b/.travis.yml
index ff23150..dee4eb2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,6 +3,7 @@
   - 1.3
   - 1.4
   - 1.5
+  - 1.6
   - tip
 install:
   - go get -t ./...