fix adding item with no barcode

a new item in a box with no barcode now gets its barcode set to None
instead of '', preventing an error.

fixes #112
add costco links to boxes and item
add search to restock

can now type in whats on receipt to add item rather than having to know
what cryptic shit is on there.
add "DEBUG" to page title

when in debug mode
raise deposit limit for good customers

if purchase > 10 and deposit > 10 then you can deposit up to 100

fixes #111
fix local js
added sql backupts to gitignore
removing print that i forgot about
add 404 handler so 404 redirects home

fixes #105
add item info graph to item edit page

fixes #109
sales tax and bottle dep are properties

makes restocking easier

fixes #119
show barcode and numbers in restock

make sure you are adding the right thing by comparing to the receipt
barcodes use box barcode if possible

fixes #118
show out of stock seperately

fixes #116
add cashdeposit and ytd

better index page and added cash deposit

fixes #94
change how cash deposits work

much clearer that you can edit a deposit

fixes #118
improve index page

add more information
round coupon to 4 decimal

fixes issue where undoing a restock gave a different total
added mcard script to all frontend pages

well except the purchase page

(hopefully) fixes #81
add users graph to index