Add DocBlocks to Gasoline\Message

* Update all methods of Gasoline\Message to have DocBlocks
* Move \Event::register('shutdown') from GASPATH . 'bootstrap.php' to
Message::_init()
Merge branch 'develop' into feature/core
Move folder themes from fuel/app/ to fuel/
Add a base and authenticated controller

Also add 404 routing to 'base/404' with a dedicated template and view
Fix bug in Gasoline\Message not using \Event
Add routes for _404_ => 'base/404'
Update bootstrap themes to add some stats to the footer
Add two controller templates Controller\{Base,Authenticated}
Update Controller\Welcome to use Controller\Base
Update Controller\Base

* Now fixed bug with status=200 on a 404-page
* 404-status is thrown and 404-pages are shown whenever a controller or controller/method is accessed that does not exist like e.g.,
    example.com/<controller exists>/<unknown method>
  or
    example.com/<unknown controller>
  or
    example.com/<module>/<unknwn controller>
  or
    example.com/<module>/<controller>/<unknown method>
Update \Gasoline\Message::render

* Add arguments $before and $after to wrap the messages in tags other
than the ones specified in config/message.php
* Change name of config options for \Gasoline\Message
Update \Gasoline\Message::set()

Add logic to handle passing $message as type \Validation_Error to
Message::set()
Add \Gasoline\Message::validation_errors()

Allows for setting the validation errors to the active message-container
Update \Gasoline\Message::set() with some speed enhancements
Fix some bugs in Controller\{Authenticated,Base}
Fix bug in \Gasoline\Message
Add package::Auth to always_load; add config/auth
Update Controller\Base to extend \Controller

* Also add _404_ route to new controller Controller\Error::router()