Merge branch 'nightly' into 'nightly'

Merge branch 'nightly' into 'nightly'

getParent() method will fail if the parent notice does not exist in the notice table

getParent() method will fail if the parent notice does not exist in the notice table. See https://quitter.no/notice/709400

There are situations where a user delete his notice which could be a parent notice to a reply.
The user which replied to this deleted notice will then have broken timeline.
This is caused by the Notice.getParent() method which tries to return the selection of non existing parent notice.

I've tried this code on quitter.no and it seems to work.

See merge request !35