Remove the dependency on the Registry package

This also removes two inherent dependencies via the `Registry` package:

``` sh
Michaels-MacBook:application mbabker$ composer update
Loading composer repositories with package information
Updating dependencies (including require-dev)
  - Removing joomla/registry (1.1.2)
  - Removing joomla/compat (1.1.1)
  - Removing joomla/utilities (1.1.1)
```