Log Message:
snac: update to 2.50. Changes:

Incoming posts can now be filtered out by content using regular
expressions on a server level (these regexes are written in the
`filter_reject.txt` file at the server base directory; see `snac(5)` and
`snac(8)`).

Improved page position after hitting the `Hide` or `MUTE` buttons (for
most cases).

Use a shorter maximum conversation thread level (also, this maximum
value is now configurable at compilation level with the
`MAX_CONVERSATION_LEVELS` define).

Fixed a bug where editing a post made the attached media or video
to be lost.

The way of refreshing remote actor data has been improved.

Posting from the command-line now allows attachments.