This makes it easier to separately handle search and index requests
from a web server or from a reverse proxy.
If a request to index contains a query, a permanent redirect HTTP response
is returned. This should give some level of backwards compatibility
for users that have set a searx instance in their browser's search bar.
This improves the user experience by loading in the next entries shortly before him getting to the bottom. It makes the scrolling more smooth without a break in between.
It also fixes an error on my browser that scrolling never hits the defined number. When I debugged it I hit `.scrolltop` of 1092.5 and the `doc.height - win.height` of 1093, so the condition was never true.
