Added Timer: a countdown timer

**What does your instant answer do?**
It adds an interactive timer

**What problem does your instant answer solve (Why is it better than organic links)?**
One-stop search for a timer

**What is the data source for your instant answer? (Provide a link if possible)**
N/A

**What are some example queries that trigger this instant answer?**
`timer`, `countdown`

**Which communities will this instant answer be especially useful for? (gamers, book lovers, etc)**
people who need timers

**Is this instant answer connected to a DuckDuckHack [instant answer idea](https://duck.co/ideas)?**
[A few](https://duck.co/ideas/idea/995/a-countdown-timer), [actually](https://duck.co/ideas/idea/182/a-timer)

**Which existing instant answers will this one supersede/overlap with?**
wiki zci's

**Are you having any problems? Do you need our help with anything?**
I wanted to add a sound, but was unsure how to go about finding something that DDG can use.

**\*\*Note:** Please attach a screenshot for new instant answer pull requests, and for pull requests which modify the look/design of existing instant answers.
![screenshot from 2014-04-08 23 13 58](https://cloud.githubusercontent.com/assets/4411471/2651681/23ca20bc-bf95-11e3-99c3-7acbf6481752.png)

![screenshot from 2014-04-08 23 16 08](https://cloud.githubusercontent.com/assets/4411471/2651687/6a693abc-bf95-11e3-859b-b1bc685387d0.png)



```
[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)
[] Tested cross-browser compatability

    Please let us know which browsers/devices you've tested on:
    - Windows 8
        [] Google Chrome   
        [] Firefox         
        [] Opera           
        [] IE 10           

    - Windows 7
        [] Google Chrome   
        [] Firefox         
        [] Opera           
        [] IE 8            
        [] IE 9            
        [] IE 10           

    - Windows XP
        [] IE 7            
        [] IE 8            

    - Mac OSX
        [] Google Chrome   
        [] Firefox         
        [] Opera           
        [] Safari          

    - iOS (iPhone)
        [] Safari Mobile   
        [] Google Chrome   
        [] Opera           

    - iOS (iPad)
        [] Safari Mobile   
        [] Google Chrome   
        [] Opera            

    - Android
        [] Firefox         
        [] Native Browser  
        [] Google Chrome   
        [] Opera
    - Linux
        [x] Firefox
```
It was also mentioned on twitter after the stopwatch was tweeted by DuckDuckHack.
I copied the design from the stopwatch, I hope it's good :smile: