Spotlight style filtering

Hello Young, firstly thanks for the great module. I really like concepts introduced in the new 2.x branch it has greatly improved my workflow but I still find it slow to dig through the menus while developing a site.

One idea to speed things up was to add dynamic filtering to the Administration menu so I could quickly find the page I'm after, the patch attached is my first stab at adding this functionality.

Currently it's crudely applied to the #block-admin-menu, I would like to create a filter object that's easily attached to any block within the toolbar but for now this works well as a prototype (any help would be greatly appreciated).

Functionality:
A new input box will be created above the admin menu, focus to activate the filter.
Use ESC to exit the filter mode & RETURN to navigate to the topmost result.

Hope you like the idea.

p.s. This is my first Drupal patch, so excuse me it's not up to standards.