When `jQuery.noConflict` is called, the global `$` variable is not
defined. We cannot assume in the code that the variable is defined,
and instead should always make sure to import the `jquery` module
when we need jQuery.
This fixes all of the issues where we are assuming that `$` is
defined globally when we are not importing the module. This also
fixes the issues when defining the `jQuery.fn.select2.amd` modules
where we were always attaching to the `$` object instead of the
`jQuery` object.
This closes https://github.com/select2/select2/issues/2947.
There was a plan to universally use an array as the return from
query methods, but now that we've realized pagination and extra
things are impossible without it, we're going back to the return
object. Anyone looking to migrate their data should be returning
an object with the key `results` containing what they previously
returned.
This should fix https://github.com/select2/select2/issues/2898
