Easier to change configuration & smoketest
- Fixed #16: Moved all temporary files from nginx to /tmp/to avoid permissions issues on older Kernel versions (<=4.4).
- Added automated smoketest
- Made it easier to change the configuration of Nginx & PHP, see: https://github.com/TrafeX/docker-php-nginx#configuration
- Some cleanup, reformatting of the nginx configuration