get_fs_helper_funcs: return summary filepath helper
_generate_dirname: s/directory/dirname/
s/get_fs_helper/get_helper/

to reflect that its not only for storage_type=="fs"
WIP: writing separate summaries for faster reading

semi-tested for fs, untested for s3
s/summarys/summaries
assume summaries written properly
update s3 functions
convert to (actual) use of summaries

instead of results
bump version
Merge branch 'summary'