Started working on abstracting Whoops into a plugin
Merge branch 'develop' into feature/plugin-overhaul
Initial implementation of ``WhoopsPlugin``
Cleaning up ``WhoopsPlugin``
Removed all hardcoded Whoops references from ``Zepto\Zepto``
Refactored ``Zepto\FileLoader\PluginLoader``, now validates plugins to see if they implement ``Zepto\PluginInterface``
Changed ``Zepto\Router::error()`` to accept either Closures or Exceptions
Added new plugin hooks ``before_router_setup``, ``after_router_setup``, ``before_response_send``, ``after_response_send``. Also routed application errors to ``Zepto\Router::error()``
Fixed all plugins to properly implement ``Zepto\PluginInterface``
Renamed hook ``*_file_load`` to ``*_content_load``
Merge branch 'feature/plugin-overhaul' into develop