Merge pull request #6225 from RosettaCommons/roccomoretti/interactive_to_string_locale
[Foldit] Accomodate for the fact that std::to_string() is locale sensitive
std::to_string() changes its behavior based on locale -- for instance using ',' instead of '.' in countries where that's the decimal separator. This messes up the SDF file generation, so borrow a trick from RDKit to consistently switch to the uniform 'C' locale when generating the SDF.
This doesn't touch any of the other instances of std::to_string() usage in Rosetta/Foldit.
(No release notes, internal-only feature.)