[Proposal] View::prependLocation($path)

Hi, 

is it possible to implement a `View::prependLocation($path)` (+ `View::setLocation($path)`) method?

Use Case:
You create a blog, you use the default location for views. Later you want to implement a "Themer" functionality to change some of the templates without touching/editing the original ones. Right now there is only the addLocation method to append a new location, BUT then only the original template would be loaded first.

Example:

Let's assume we have a blog. And we "make" a view:

`View::make('posts.show')->withPost($post);`

By default no theme is set, so this view should be called:
`app/views/posts/show.blade.php`

Now we apply a "Bootstrap" theme, now this file should be called:
`app/Themes/Bootstrap/views/posts/show.blade.php`

if there is no such file, the original should take place instead.

With `View::prependLocation($path)` + `View::setLocation($path)` you could offer a nice and easy way to tackle even deep nested Sub-Theming like:

Look for 
`app/Themes/Bootstrap/Christmas/views/posts/show.blade.php`
Nothing found - look here:
`app/Themes/Bootstrap/views/posts/show.blade.php`
Nothing found - look here:
`app/Themes/Default/views/posts/show.blade.php`
Nothing found - look here:
`app/views/posts/show.blade.php`

(The `setLocation` method should replace all given view paths with a set of new ones)

Greetings from Munich :-)