Created method toArray() on Config class
Update documentation on README.md file.

* Created documentation for "autoloaderPrefix" provider;
* Update documentation of "php" provider.
Created "pdo" provider.

* Created class provider for PDO object;
* Updated documentation.
Created method ``getProvider()`` on Bootstrap.

* Updated documentation with examples getting the provider by name
Updated documentation

Fixed wrong example of "php" provider use.
Merge branch 'develop'