Test with go 1.4

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index c3af3ce..da5d6ae 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,7 @@
 go:
   - 1.2
   - 1.3
+  - 1.4
   - tip
 install:
   - go get github.com/stretchr/testify