Support directory parameters

• Add directory_extra_parameters allowing configuration of the Directory section on Apache. (#PR 4)
• Better extra_parameters handling inside VirtualHost section of Apache, one parameter per line instead of all of them on a single line. (PR #4)

Thanks to @ricoli for the awesome Pull Request!

Ubuntu Trusty and CentOS 6.5 support

• Fix installation on Ubuntu 14.04 Trusty.
• Fix installation on CentOS 6.5.
• Creates VMs to ease local development and testing.
• Improve CI tests.