This will prevent leaking variables, and will remove the possibility
of Select2 not working well with other plugins which support
AMD loaders. The `define` and `require` methods are now aliased
under `$.Select2.amd` for use inside additional files, such as
translations.
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.