Travis: Test with Go 1.6
diff --git a/.travis.yml b/.travis.yml
index 9a3c1a8..cdfeace 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,4 +6,5 @@
   - 1.3
   - 1.4
   - 1.5
+  - 1.6
   - tip