Merge pull request #4598 from RosettaCommons/roccomoretti/interactive/develop_master_merge2020
Foldit: Merge a recent(ish) version of master into the interactive/develop branch.
Update the Rosetta version for Foldit to a recent-ish version.
Due to the update on submodules, this includes a change on how Foldit on Windows needs to be downloaded/built (Powershell instead of cygwin, to allow MSVC to properly work with native symlinks.)