steam specials

**What does your instant answer do?**
Fetch steam specials at Steam Store

**What problem does your instant answer solve (Why is it better than organic links)?**
Get to instantly know best Steam offers

**What is the data source for your instant answer? (Provide a link if possible)**
Official Steam Store (http://store.steampowered.com/)

**Why did you choose this data source?**
Steam api

**Are there any other alternative (better) data sources?**
No

**What are some example queries that trigger this instant answer?**
steam specials, steam offers

**Which communities will this instant answer be especially useful for? (gamers, book lovers, etc)**
gamers

**Is this instant answer connected to a DuckDuckHack [instant answer idea](https://duck.co/ideas)?**
Yes, [here] (https://duck.co/ideas/idea/976/steam-sales)

**Which existing instant answers will this one supersede/overlap with?**
 Steamdb perhaps

**Are you having any problems? Do you need our help with anything?**
I wanted to include steam game info <game_name>, but that requires to fetch a gamelist (returns json with some 30k records) from steam every time a request is made and then pass the matching id for a spice call. Im not sure, this scenario fits the spice IA perfectly, what to do? 
Also please advise on the pending issue with pr #846 and #845(use of spice wrap_string_callback), so i can update accordingly. Ty.

**\*\*Note:** Please attach a screenshot for new instant answer pull requests, and for pull requests which modify the look/design of existing instant answers.
![special_1](https://cloud.githubusercontent.com/assets/1424236/3209215/7279a7ec-ee60-11e3-87b9-21ee6c780ff0.png)
![special_2](https://cloud.githubusercontent.com/assets/1424236/3209216/7f0a7d7e-ee60-11e3-9310-4867b7a14cc1.png)

##Checklist
Please place an 'X' where appropriate.

```
[X] Added metadata and attribution information
[X] Wrote test file and added to t/ directory
[X] Verified that instant answer adheres to design guidelines(https://github.com/duckduckgo/duckduckgo-documentation/blob/master/duckduckhack/styleguides/design_styleguide.md)
[X] Tested cross-browser compatability

    Please let us know which browsers/devices you've tested on:
      - Mac OSX
        [X] Google Chrome   
        [X] Firefox       
```

@killerfish Awesome, ping me when you're ready for review. :)