Add pubdate

Add pubdate with a good format, against publishedDate.
UX and HTML corrections

Put the infobox first. Result first is more useful for the user.
Add id in form for "for".
htmlentities in the URL.
Take care of spaces in categories.
Add alt for img

Add alt in infobox image.
Bug + HTML corrections

Add alt for favicon
Correct datetime format
Remove pubdate (not in html5 spec)
Don't use pretty_url for web.archive.org.
UX + HTML corrections

Add title on image for hover
Add alt on favicon
HTML corrections

Add alt on favicons
Use right format for datetime
Remove pubdate tag
Bug + HTML corrections

Add alt on favicons
Use correct datetime format
Remove pubdate tag
Use url instead of pretty_url for web.archive.org
Bug + HTML corrections

Add alt on favicon.
Use correct datetime format
Remove pubdate tag
Use url instead of pretty_url for web.archive.org
Add alt on video image
Striptag on alt and title

Strip HTML tags on alt and title of the images
[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)
Merge pull request #142 from Cqoicebordel/Fix-Google-Image

[fix] Google image with special chars
Merge pull request #141 from Cqoicebordel/UX+Bugs+HTML

UX+bugs+html
[mod] search thread names
[doc] @Cqoicebordel added to authors
[enh] v0.5.0
Merge pull request #2 from asciimoo/master

Update