Winners gallery functionality.

Modal and Slideshow for Winner's Gallery. Both the modal and the slideshow are progressively enhanced and responsive. Both are JavaScript modules which could potentially work on other projects. They've been coded with the intent to be modular and completely separate styling from the functionality. Both the modal and slideshow can be fully customized visually via custom CSS.

Resolves #396

See screenshots below for depictions of how the progressive enhancement looks and for visuals on small and large sizes.

@DFurnes 

**Progressive Enhancement on small screen**
![mobile winner s gallery](https://cloud.githubusercontent.com/assets/105849/4794196/1de9b2e6-5df3-11e4-8136-5d66fdb32361.png)

**Progressive Enhancement on large screen**
No JavaScript:
![javascript not working](https://cloud.githubusercontent.com/assets/105849/4793943/9f7de860-5df1-11e4-94c6-8f3c7be774a6.png)

With JavaScript:
![javascript working](https://cloud.githubusercontent.com/assets/105849/4793947/a3fa8e34-5df1-11e4-8bcf-3035c8e2fb5e.png)


JavaScript Modal:
![javascript modal](https://cloud.githubusercontent.com/assets/105849/4793949/a6596f74-5df1-11e4-9f02-be9a5657d814.png)

CC: @angaither @barryclark @jonuy (Uy, I added you since you were curious about the JS!)