Fix routing for altered url

When I type in www.gooGLE.com, I will still get to the page I want.
The same should go for URLs in my routes.
When a user alters a link by using capital letters, it is considered wrong.
Even if a route is found.

This change makes sure that all string entries eg. controller, action, plugin are in lower case, when finding a route match.

So that my route will find /cakephp and /cakePHP
```
Router::connect('/', array('controller' => 'cakephp ', 'action' => 'index'));
```
So if a user enters