Add Travis CI.

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index fbfdd15..82af4fd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,6 +3,7 @@
 
 jdk:
   - openjdk7
+  - oraclejdk7
   - oraclejdk8
 
 # only build master and the MATH_3_X branch