Merge branch 'oembed_branch' into 'nightly'

purify oembed html and don't allow cdata

hopefully we never need stuff in cdata

reason for this is that this link serves javascript in its oembed data: https://www.maketecheasier.com/switch-windows-10-to-linux/

see:
https://www.maketecheasier.com/wp-json/oembed/1.0/embed?url=https%3A%2F%2Fwww.maketecheasier.com%2Fswitch-windows-10-to-linux%2F

i don't feel we want that in our database.

See merge request !79

diff --cc lib/util.php
Simple merge