bump version 2.2.0

Minor improvements and features added.

• Project directories structure updated.
• Missing translation for invalid hostname added.
• Symfony versions for travis-ci tests added.
• phpunit tests updated.
• Support for multi-language based sites added.
• README file updated.
• Cached .gitignore file fixed.
• The last stable version of phpunit has been stablished as the default one for running tests.