Storyboard support

Fixed the storyboard support and added a very basic example.
Changed the way the menu is displayed, it now takes the whole width of the screen, this makes it easier to design.
Align completely left for the left menu, align completely right for the right menu.

Fixed issue #1 with this pull request, this time for real.

-- Extra commits --
Implemented the 'full screen menu' feature when tapping a textfield.
Check the AppDelegate.cs class well since it requires some implementations on the menu class before this feature works.