Fix php-curl-class#34: Add PHP 5.3 to continuous integration tests

Author: zachborboa

.travis.yml

@@ -1,5 +1,6 @@
 language: php
 php:
+  - 5.3
   - 5.4
   - 5.5
   - 5.6
@@ -12,4 +13,6 @@ before_script:
   - php -S 127.0.0.1:8000 -t tests/PHPCurlClass/ &
 script:
   - php -l src/*
-  - cd tests && phpunit --configuration phpunit.xml
+  - if [[ "$TRAVIS_PHP_VERSION" != "5.3" ]]; then
+      cd tests && phpunit --configuration phpunit.xml
+    fi