[enh] add photon engine, and fix pep8 errors

[fix] fix kickass engine

thanks @Cqoicebordel in #144:
https://github.com/asciimoo/searx/pull/144#issuecomment-67036903

[enh][oscar_template] replace kickass icon

Kickass torrent search engine

Add kickass in engine list
Add content for the result from kickass

Html+Bugs in templates

Add the alt in favicon

Alt on favicon
No <p> in <p>
Correct alt and title on img

Put the result URL at the top, like in other results template
Put the magnet link on the same line as the stats (peer/seed).

Alt on favicon
Width of image should be 400 and not 400px
Correct alt+title on image
No <p> contains <p>

Courgette was using the wrong template. I assume it was a mistake.

Parse and return results correctly. Pages numbers taken care of.

Not done, and maybe to do :
- 'content' : I don't know what it could be. Maybe votes ?
- 'categories' : the results are not filtered by categories, because I don't see how to do it properly : there are too much categories on Kickass. Is 'video' only movies, or also tv show or porn ? So for now, the category is 'all'.
- Favicon/icon : may be a good idea.

UX+bugs+html

[fix] Google image with special chars

It seems like Google image is doing a double urlencode on the url of the images. So we need to unquote once before sending to the browser the urls.
It solves the 404 we could see with some image with specials chars in url. 
Exemple https://searx.laquadrature.net/?q=etes&pageno=1&category_images (there are two of those in the list)