Updated UI to better work with the vendor lib
Checkpoint: spiking on random path to fix coin issue
Machine is now keeping track of balance, and initializes with a balance of zero
Refactored how we track quarters
Vending machine checks for quarter quanitity before purchasing gum
Shopper can now purchase twinkie for three quarters
Fixed a bug where a shoper can buy twinkies at a discount
Clears screen after dispensing product
refactored like dispense functions