* Added XML routing configuration (symfony/config)
Modified structure to reflect that controllers must return a Response.
Agregue mi ejercicio
Agregue Save Book.
Mezclo aaciones de login con guardar libro
Merge pull request #2 from enriquehf/master

Pull Request
Merge pull request #3 from kayec/master

Acción de descargar libro
Agregue compartir libro
Merge pull request #4 from Claud1a33/master

share-book
* Removed pages folder
* Fixed search books action
* Fixed some URL paths
Merged upstream.
Merged upstream with fixes.
Merge pull request #5 from MontealegreLuis/routing_config

Routing config
Added missing routing configuration.
Merged respose changes.
Merge pull request #6 from MontealegreLuis/request_response

Request response
Updated controllers that were not returning a Response object.
Added controller resolver component.
Added HttpKernel with routing and error handling events.
Added dependency injection component.