When using array data, and an option is selected, the data that is
attached to the DOM element will be run through `item` and should
have any private, automatically generated attributes added and
merged with it.
We should only be checking the option values that matter, such as
`id` and `text`, instead of checking all of the option values. This
will prevent unexpected breaking when new properties are added to
the options.
Existing properties should be covered by tests to avoid regressions.
We have to enforce ids being strings as the values of options within
a select will always be an id. This fixes an issue that we had with
array selections not being highlighted in the results.
This adds decorator support in a very basic way, but enough that
it doesn't take a lot of effort to get it implemented.
This also starts work on splitting things out for theming.
