Added sonar-scanner to Travis-CI

Author: radek-ziemniewicz

.travis.yml

@@ -21,4 +21,4 @@ install: composer update --no-interaction --no-suggest --no-progress
 
 script:
     - phpdbg -qrr vendor/bin/phpunit  --coverage-clover phpunit.coverage.xml --log-junit phpunit.report.xml
-
+    - sonar-scanner