Image control broken in 4.1

[csloisel]

Does not appear broken, but it is not loading the custom output or js. It is using the core functionality and it is no longer returning an id when trying to use that as the output format.

The core upload control that is the parent of the class we are extending no longer uses render_content() and instead calls a content_template() method to print a js template.

Haven't checked the other controls, they may not be working either.