Torrents w3c+ux+rss

Add non exclusif bang

Puts links to torrents and magnets in tool bar
Fixes a lot of W3C errors

Little fixes, add searx-autocompletion, more informations about torrents

Conflicts:
	searx/engines/vimeo.py

Minor fixes

New "embedded" item for the results, allow to give an iframe to display the media directly in the results.
Note that the attributes src of the iframes are not set, but instead data-src is set, allowing to only load the iframe when clicked.

Deezer engine based on public API (no key).

Change URL from https to http
Change way of handling text xpath

Allow to perform a search while adding an engine (or a category) without adding it "officially" to the request.
'?' is used to add an engine without modifying anything else to the request. For example, you can perform a search in the 'general' category, and if you add '?tw' the result from Twitter will be added to the originals results.