allow Quest Scrolls to be sold for Gold (website and API UI)

Allows a player to sell quest scrolls for gold in the same way that food etc can be sold for gold. Works on Inventory page and through the API Swagger UI.

**Requires PR** https://github.com/HabitRPG/habitrpg-shared/pull/417

Includes a new test in `test/spec/inventoryCtrlSpec.js`.

Adds a new style to `public/css/shared.styl` to allow word-wrapping in the blue "sell" button (see image below). Tell me if there's a more preferred way/place to do/put this. Without wrapping, it's a single-line button that stretches well out of the right-hand side of Alexander's box. 

I'll merge this in a couple of days if there's no complaints.

![screen shot 2014-12-29 at 5 14 26 pm](https://cloud.githubusercontent.com/assets/1495809/5566827/1f1dd14c-8f80-11e4-8ae7-c801610516be.png)

Does it even need this check? All it's doing is canceling the item from being available to be sold to Alexander. 

Since clicking on the quest will open up the modal again, I'd probably expect it to persist in Alexander's speech bubble anyway.