Virtual Host support

Adds support for virtual hosts to the framework.

- Environment configuration has a new method `EnvironmentConfig::useVirtualHost()` that returns a boolean value
- `PathGenerator` implementation will create appropriate URL path if virtual host support is enabled
- Changes implemented `\SprayFire\Http\Routing\MatchStrategy` implementations to work with URI paths that may or may not have trailing and leading slashes
- Adding some tests to ensure appropriate virtual host changes are implemented properly