Merge pull request #57 from mentalstring/master

Replace `dirname(__FILE__)` by `__DIR__` since PHP 5.3.4 is required
Use late static binding for config classes (PHP 5.3+)
Merge pull request #25 from LExpress/late-static-config

Use late static binding for config classes (PHP 5.3+)
PHP built-in webserver compatibility

`sf_cli` should be `false` when running with PHP built-in webserver (PHP_SAPI == "cli-server"). It is a web-environment, not CLI, though it is initiated with CLI command.
Merge pull request #58 from e1himself/patch-1

PHP built-in webserver compatibility
Use composer in travis
Merge pull request #61 from jeromemacias/patch-1

Use composer in travis
Merge pull request #59 from mentalstring/master

update swiftmailer to >=5.2.1