* cs fixes + update composer.json (add psr/log to reguired and monolog/monolog to suggested dependencies)
* fix .gitkeep issues marked by .gitignore PhpStorm plugin (replace non-standard .gitkeep with standard .gitignore)
* Implement integration test suite for #10
- Update composer dependencies
- Update test cases for updated phpunit
- Add more logging
- Add default ttl for SimpleCache::set() method call
- Implement integration test suite (guzzlehttp + symfony/process + built-in PHP web-server)
- Add integration test for internal PSR-16 filesystem-based adapter (tests are failing)
- Add PHP7.1 and PHP7.2 to Travis CI config
- Issue-related tests added to group "issue10" and can be selected by "--group issue10"
* Increase default expiration time to 60 seconds
* Updates for issue #10
- Pull upstream updates
- Update code to pass PSR-16 compliance tests
- Implement TTL logic in default PSR-16 filesystem-based adapter
- Update tests` annotations for better phpunit report
* Fix random_int issue int IntegrationWebServerTest
* Fix path to router script for built-in php web-server in IntegrationWebServerTest
* Replace random_int() call with rand() in IntegrationWebServerTest for PHP5.6 compatibility
* Revert tests with exceptions to upstream version for PHP5.6 compatibility