MMOspy spout is broken and Teltarif contains advertising system
artifacts or something, which makes the FullTextRss filters better
for these sites.

To improve their quality and lower the maintenance burden, the spouts
were modified to use FullTextRss (Graby) spout.

In the future, the spouts can be completely removed and users migrated
to the actual FullTextRss spout.

See also: #935

In 2015, Facebook removed its feed support. Unfortunately,
it is no longer possible to access the site content
programmatically without registering an app.

This patch switches to the new API and adds fields for entering
the app credentials.

Closes: #687

Pro-Linux works slightly better with FTR, for example the current
spout does not seem to include images.

SimplePie_IRI is supposedly buggy and SimplePie wants to get rid
of it in favour of some networking library anyway.