Added a Travis CI build file.

This allows for continuous integration builds by travis-ci.org.
More information at https://docs.travis-ci.com/user/languages/cpp

.travis.yml

@@ -0,0 +1,13 @@
+language: cpp
+compiler:
+- clang
+- gcc
+os:
+- linux
+- osx
+sudo: false
+before_install:
+- echo $LANG
+- echo $LC_ALL
+script:
+- make -j 4 check