Need a way to block messages from a user

There is currently no obvious method for blocking all messages from a user. For individuals who send an @-reply we can block them, but if they start spamming a group we are a part of then there's no way to block that users messages.

Either the Block button needs to ensure that no messages from a blocked user are seen (which needs to be reflected in messages fetched using applications) or there needs to be a way to report posts and accounts that serve no purpose other than advertising/spam.