small convenience updates

Added:
- Added some functions for other convenient reports.
- print_all_orders() shows everything, instead of just things close to
selling out.
- print_idle_orders() gets things that have not sold this week and sorts
least profit to the end (where you're likely to see it first) instead of
most profit.
- print_exhausted_month() reports everything that's 100% sold out and
sold stuff this month.
- print_urgent_orders() now requires sales this week instead of this
month.
- Fixed some strange behavior discovered while adding the functions.
added a readme