astronomy picture of day

**What does your instant answer do?**
 Display astronomy picture of the day

**What problem does your instant answer solve (Why is it better than organic links)?**
 Saves a click

**What is the data source for your instant answer? (Provide a link if possible)**
 Astrobin, http://www.astrobin.com

**Why did you choose this data source?**
 One of the best sources i found (willing to let us use their api).

**Are there any other alternative (better) data sources?**
 Might be in the future.

**What are some example queries that trigger this instant answer?**
apod, astronomy picture of day, astrophoto m31

**Which communities will this instant answer be especially useful for? (gamers, book lovers, etc)**
 general users.

**Is this instant answer connected to a DuckDuckHack [instant answer idea](https://duck.co/ideas)?**
 Yes, [here](https://duck.co/ideas/idea/373/astronomy-picture-of-the-day)

**Which existing instant answers will this one supersede/overlap with?**
 apod actually triggers zipcode as well, any ideas how to tackle this issue?

**Are you having any problems? Do you need our help with anything?**
 ^previous question.

![apod_final](https://cloud.githubusercontent.com/assets/1424236/3530325/5aeab308-07a3-11e4-91a2-af753dda9bf5.png)
![apod_final2](https://cloud.githubusercontent.com/assets/1424236/3530327/5af569d8-07a3-11e4-9961-72183c5b231e.png)
![apod_final3](https://cloud.githubusercontent.com/assets/1424236/3530326/5aeda2de-07a3-11e4-9dc5-f2e06c502493.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         
```
I think `sourceUrl` should point to the actual image (like http://www.astrobin.com/109354/ for today)