[Minor Upgrade] Expansion Game Playability & Next Purchase Recommendation

[Shad]

Hi everybody!

I've expanded upon the Scenario Requirements & Playability module found on each scenario's page and created the:

Expansion Game Requirements & Playability module!
(clearly not investing a lot of time in cool naming schemes...)

This can be found on the Library Game page for every expansion game.

It does four things:

1. tells you which games are required to play that expansion's scenarios
   
2. tells you how many scenarios in which each game is used
   
3. analyzes your collection and tells you how many scenarios you can play right now
   
4. analyzes your collection and tells you which game you should purchase next to maximize your playability
   

Obviously if you are a non-member or logged-out, only the first two functions are active. (you have no collection to analyze)

The module is pretty straightforward. Those of you with near-complete collections, or who have bought most of the key "source" games will find the tool less useful. There's no getting around that.

For people just getting into PG, or who have limited collections and are looking to make careful acquisitions, this should be a welcome improvement.

For me? Well, every page is a constant reminder that I really need to go fucking buy Edelweiss: Expanded!

Enjoy!