Flesh out seller stats page for live auctions

[zachgoldstein]

As bids come in on an active auction, a live-updating page with show sellers data about their auction. Data to show in this page:

• List of bids & price
• A chart, based off bid prices, ordered descending by price, that illustrates the demand curve for the product
• A display of the current sale price (Number of items for sale "th bid" + 1). So if there are 10 items for sale, then this is the 11th highest bid.
• A display of the average overall bid price
• A display of the average bid price for top (items for sale) bids. Ex: if 10 items are for sale, this is the average of the top 10 bids.
• If top bids are much higher than overall average bid, a message recommending that the seller consider doing commissions
• If there are way more (?? 10x ??) bids than there are items for sale, a recommendation that the seller consider a larger run of the product at the overall average bid price

[zachgoldstein]

Added a new vickrey.py class with the guts of the logic here. Used a protocol class to keep it decoupled from Django so it's easier to pull out later into a separate library. Added a stats page that just dumps the basic vickrey results based on the list of bids. Next need to flesh out the markup and add some basic logic around the recommendations

[zachgoldstein]

Added tabs to stats page, fleshed out super basic recommendations and moved auction edit page into a reusable page. Markup & layout is really rough but data is in there. Charts for bid price data has been moved out to https://github.com/zachgoldstein/vickrey_auctions/issues/11 Leaving this open for now, page is not polling for updated data yet.