Add Go 1.2 to the build matrix

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index 17a616a..90958b0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,4 +2,5 @@
 go:
     - 1.0
     - 1.1
+    - 1.2
     - tip