Rewrite requests

Rewrite the request infrastructure to facilitate more interation and to
intrinsically enforce some of our policies (must sell at known store, must
provide URL if you can, etc).

This also moves requests to logged-in users only, which should help following
through on confusing requests.

Fix NAN% issue in terminal

Happened if nothing was in the cart and user is >5 in debt.

Remove coin deposits

Hid the button

Better Add User Purchase UI

Show the in_stock quantity for adding user purchases.

Better UI for Validating Deposits

1. Show cash deposits that should be reflected in each cash box empty.
2. Don't merge manual cash deposits.

Checking off old issues

• support balance transfers between people
• clean up items page
• add histograms
• show transactions on pool pages

Add Bill Acceptor

Replace manual deposits with automatic counting using a bill acceptor. Also support scanning items on the login page and having them be added to the cart when a user logs in.

Add sticky price support

Small database migration to add a new column to the items table to support sticky prices (items whose price is fixed).

Fix bug with WoS fee

• Missing one - sign.

Up wall of shame fee

• WoS fee now 5% + 5% for every additional $5
• Also charge WoS fee on all charges that cause a user to go below $5
• Update users page in admin view.