CSFloat Item Popup Enhancements

[GODrums]

CSFloat

The item popup displays past sales in a graph or a table (when clicking on "Table"). This table is currently untouched but can be enhanced by many useful features very similar to what the extension is doing in other places already.
Exemplary features:

• calculate sticker percentages
• price difference/markup to Buff (careful: current prices may be substantially different to past prices)
• link to the original listing

Possible positioning for those features:

The item popup further displays "Similar items" which are in the default state pretty useless. They could get pimped up with more basic details (all available via the API data):

• name
• price
• csgostash links

[GODrums]

Partly addressed and integrated with commit 37138f0.

[GODrums]

Still missing are:

• enhancing the "similar items" section with basic details, e.g. price, pattern, stickers
  
• enhancing the "buy orders" section with interesting details, e.g. difference to item price
  
• create more action items to quickly access important links: Csgostash, Pricempire, Steam inventory link, screenshot button?