BearCollector: Add default directory
CLI Params: flat_bear_directories->flat_bear_dirs
CLI Params: rec_bear_directories->rec_bear_dirs
processes: Add Barrier

This will be needed for the SectionExecutor
BearRunner: Add Barrier

This barrier may be used to ensure global resultts are sent through the
queue only after local ones are all through.
processes: Add SectionExecutor
processes: Add SectionExecutorTest