scbs filter should preserve the run_info log file

[LKremer]

scbs prepare writes a data_directory and a log file denoting the scbs version number and the command line parameters that were used.
scbs filter takes a data_directory and creates a new, filtered data_directory. But it doesn't copy the previous unfiltered run_info.txt file. It should copy at least copy the log file and maybe append one line to log the filter parameters.