Dependency Updates

I have updated the dependencies of this library to allow for versions of Symfony Console and Doctrine DBAL > 2.4.

Additionally, I swapped out the dependency on Zend\Config for Symfony\Yaml, and updated YamlLoader to use the Symfony Yaml Parser.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes