This addresses a number of issues with the classic classhelper. It does not address
issues with the calendar popup that uses the same basic classhelper mechanism.

https://github.com/UMB-CS-682-Team-03/tracker was created by a team at U-Mass Boston
to upgrade an existing classhelper link using a web component. It needs access
to the rest interface to operate and it needs web component support from the browser.
If either of these fails, the component will drop back to the classic classhelper.

Get this into the 2.4.0 release. Document by updating:

  upgrading.txt
  admin_guide.txt

install in classic tracker template. It doesn't look like it's used in the minimal
template to the jinja template. devel and responsive use it, but I want to get some
experience with it and I think the classic template is more heavily used.

Also user_guide.txt needs to be updated along with an image of it in use.

added rest endpoint /rest/data/user/roles so user doesn't have to use interfaces.py.
Because I am adding it to rest.py, I can control the order of application under
python3 at least so that the endpoint can live under the data/user endpoint.

test of endpoint works for python2 as well.

Done for now. If any issues are found, I'll open a new issue.