add library genesis engine

fix paging of duckduckgo

[mod] searx uses flask framework only in webapp.py

darker green for result url

[enh] make navbar smaller

[enh] make number of results less prominent

more compact results in Logicodev style

Input check

What has been moved into this template :
* opensearch*.xml is always the same whatever the themes.
* the text inside */about.html

Semantic Scholar

[enh] show spelling corrections

[WIP] Add 1337x.to engine

[fix] searching for "!google_images text" doesn't work

[mod] /config API : add more fields for each engine

Remove pyasn1-modules from dependencies