Added util_background_exec proc and friends for executing chunks of code in a background thread in a safe manner. There seem to be some thread issues, though :(
- Moving Malte's enhanced survey from the accidentally-created "oacs4" repository he created into openacs-4/contrib.- Malte's commit line was: "Added new survey module version for head."
making sure import_from_files proc does not produce error messages trying to find correct charsets for a locale if there are no files for that locale anyway