Enhanced the "apparent events table writer" module so that it also shows exams and traces. Removed the output variables in detection-monitor, vaccination-monitor, and destruction-monitor that are now better presented via the apparent events table writer.
Added an "exposures table writer" module. Removed the variables in exposure-monitor and infection-monitor that are now better presented via the exposures table writer. Removed the exposures_table_filter from the filters directory because it is obsoleted by the exposures table writer module. Fixed the CLEANFILES rule in the filters directory to clean up the intermediate files produced by bison.