And test go 1.5 while we are at it

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index c40fb69..df435a0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,6 +5,7 @@
 go:
         - 1.3
         - 1.4
+        - 1.5
         - tip
 
 install: