fix ages again. rework get month to be consistent.
API: get_earnings_panel -> get_earnings_joined
put writers into functions.
ENH: more helpers for labor flows.
update age. more stuff for flows.
change name to panel_store
start tracking notebooks
BUG: use index.names instaed of hardcoded.
BUG: wrong name for dd lookup
print output
BUG: Keys on earn were incorrect.

I'm selecting frame 4 (months +3 and +15) and 8. I only shifted forward
12 months instead of 15.
BUG: error type
clean update_panels after running
partial impl of race fix