user ember v1.4 - 1.5.1

update tests with new test helpers
fix issue with keyboard navigation order

when adding a menu-item conditionally (i.e. based on a computed
boolean), ensure that menu list items are kept in sync with the visual
layout of them. this ensures that keyboard navigation is consistent with
the visual order of items in the menu.
only consider registered items on item list

dont consider child view items within item list unless they have
registered themselve with the item list. allows for using other
components as children that dont get focus
Merge pull request #10 from knomedia/keyboard-order

keep keyboard nav order consistent with visual layout