index_files to be defined at server level if specified in resource::vhost

This partially avoids pitfall #2 (http://wiki.nginx.org/Pitfalls)
Force index_files to Array before iteration in templates
Merge pull request #204 from openquery/index_files_to_serverlevel

index_files to be defined at server level if specified in resource::vhost
provide visibility of Travis status
Merge pull request #206 from 3flex/travis-badge-in-README

provide visibility of Travis status
Add the possibility to add a header to the HTTP response  when response code is equal to 200, 204, 301, 302 or 304.
Fixed long names virtual hosts, such as nginx::resource::vhost { 'name1.domainname.org name2.domainname.org': }
Merge pull request #209 from abraham1901/dev

Bugfix: Fixed long names virtual hosts
Implemented input validation - type hash - for the (optional) add_header parameter.
Merge pull request #208 from hdanes/add_header

Add the possibility to add a header to the HTTP response