Merge pull request #6563 from RosettaCommons/roccomoretti/load_with_secret_keys
[Foldit] Allow (scientist) loading of expired puzzles.
It would be helpful to be able for scientists to load expired puzzles. That's currently not possible through the standard client.
However, there is a secret key combination of CAS-N which was set to load specific Dojo puzzles. This functionality can be extended to download and launch any puzzle.
Attempting to launch an old-server puzzle (that is, a puzzle without file contents) will result in a crash -- as this is a secret key functionality, that should be okay.
(No release notes -- internal feature only.)