Fixed clearing of selection using the delete key.
If allowClear is false, display text now reverts to that of the last confirmed selection if the dropdown is closed
with no item matching the search text.
Allow adding of custom text via enter key as well as by clicking on "+" icon.
Removed initialText setting, which is not needed as text can be taken from the ac-model object.
Removed unused itemID variable.
Addtional jasmine test and updates to test page.