module subversion, export option

Hi,

The subversion only offers to “checkout” (or update) the code. The pull request offers a “export” option that allows to export the code. It feels cleaner in production to not have the .svn directories and permits to archive every deployed version in a “static” (non updatable way).

Pull request: https://github.com/ansible/ansible/pull/5279

Regards,
Baptiste Lafontaine