rjdev branch

Hey

As far as I can check everything seems to work just fine with my code now, so I think it's good enough for us to merge dev branches and continue working off the same footing.

Most notable changes I've made:
- General code cleanup, easier to follow the extensions flow; everything has its own scope - global scope should be cleaner now.
- Refactored subscriptions_savings_check; it is now a lot simpler, and all in one place - no global scope dependencies.
- Refactored coupon-related code; it is now a lot simpler to interpret.  The coupon info now also shows up on pages of apps you already own.
- Added tags alongside highlights, to show more information about an apps state than a highlight alone.
Tags and highlights have their own checkbox in options, so users can select either or both
- Added a tag that states how many friends have an app in their wishlist. (new feature)
- Added empty wishlist button (new feature).
- Started using storefront API where appropriate, though it is still not fully capable of replacing the scraping we do (need it to return whether an app is owned or not, I've put in a request for that attribute to be added).
- Added highlighting for items in inventory (this was disabled but WIP in your code, I think).
Gifts and Guest Passes are distinguished from eachother in tags.
- Removed uses of http/https that were potentially causing problems; code now uses "//www.whatever" so it matches whichever protocol the page was loaded with.
- Extension code now runs on $(document).ready, so there shouldn't be any potential firing-too-early issues.
Code here is also URL aware, so methods don't get called on pages where they're not needed.

I think that's the gist of it.  The only behaviour I'm not sure in right now is how a coupon's saving will interact with a discounted game.  I'm fairly certain my implementation will play nicely with it, but regardless - that specific case has not been tested.

There is also still the case of widescreen-certifications and dlc categories not giving data for any appids I've tried, so their behaviour with my code changes is also still unobserved.

Here are some screenshots demonstrating the tagging changes: http://imgur.com/a/uTF5n