Port the changes from contao/core@79d45a9f4dac02c3078a55fc531c746bce8e2c4f
Remove a redundant `mkdir()` call
Port the changes from contao/core@cd66d61d3d1aa25294808fbede392d4fecc93cc2
Merge branch 'develop' of git://github.com/contao/contao-library into feature/symfony2

Conflicts:
	src/System.php