Add travis config file

Author: brexis

.travis.yml

@@ -0,0 +1,14 @@
+language: php
+
+php:
+  - 5.4
+  - 5.6
+  - 7.0
+  - 7.1
+
+before_script:
+  - composer self-update
+  - composer install --no-interaction
+
+script:
+  - vendor/bin/phpunit