This also adds more documentation and corrects the release notes
for these breaking changes. These modules will now only be included
in the full builds of Select2, which has been noted in a few places.
This adds detailed docs explaining how you can convert the old
implementations of `query` and `initSelection` into a custom data
adapter using the `current` and `query` methods provided there.
Examples are included that should make it considerably easier to
handle.
The documentation for templates still needs to be created.
A warning is now generated in the console for applications using
the previous data attributes that have been migrated.
