Everything is working (as far as I know), notes on how this submission works below. 

Changed my base tag so it should work regardless of http or https, as far as my testing has gone I haven't noticed any issues (or have fixed them) from this. 

I handled the checkout service a bit differently than the direct outline, which I think should be fine since we're allowed to customize a bit. 

Notes on this:
    1. The cart doesn't use a quantity box, instead uses +1 and -1 buttons to edit quantity. 
    2. This means I only have orders and order items "IP" or "PD" for in progress or purchased, which prevents orphan orders. 
    3. These + and - 1s still handle quantity issues, removing the item from the cart at 0 and stopping increases past in stock amount while alerting the user
    4. I used one big script called handle_cart.php for all the cart related functions
    5. Quantities available only update after a purchase is completed.

handle_cart starts with a bunch of cases because I had to do this weird thing with scripts in my shopping cart page to update stuff and remove items from cart, and 
calling the handle_cart functions directly was being odd. Using the scripts did allow me to reload the page easily which is the easist way I could show the new cart values
on the shopping cart page as they were incremented or decremented. 


Note on S05: 
I lost points on the last subimssion for not having 2 separate SQL tables for products and categories even though the outline said that didn't matter ;(