Added prepended config files as a container resource.

This allows to track changes during debug.
Also added `file_get_contents()` to `Yaml::parse()` in order to be
compliant to Symfony 3.0
EZP-22610: Adding canonical link on all defined content
Merge pull request #65 from flovntp/canonical

EZP-22610: Multi-location and canonical links
EZP-21846: Contact form using symfony
Merge pull request #64 from ezsystems/fileresource

Added prepended config files as a container resource.
BDD: fix BrowserContext namespace for the refactoring
Merge pull request #56 from ezsystems/ezp-21846-contact_form_symfony

EZP-21846: Contact form using symfony
Fix EZP-22627: Place listing is not language aware
Merge pull request #67 from ezsystems/ezp-22627-place_listing_languages

Fix EZP-22627: Place listing is not language aware
Merge pull request #68 from MLoureiro/bdd_browser_refactoring

BDD: fix BrowserContext namespace for the refactoring
EZP-22605 Implement a button to diplay an unsorted placeList