Support Maproulette cooperative challenges

[Cj-Malone]

Description

Maproulette cooperative challenges are special challenges that give the user data to work with, eg a new node.

@mvexel will be able to better explain, with JOSM it looks like there is an extra request, eg:

http://127.0.0.1:8111/import?new_layer=false&layer_name=MR%20Task%20215603166%20Changes&layer_locked=false&download_policy=&upload_policy=&url=https://maproulette.org/api/v2/task/215603166/cooperative/change/task_215603166_change.osc

Along with the load and zoom call.

Rapid would have to load that osc file.