Revisited MessageFilter::test_condition() to allow && and || constructs
We can now use something like
?item_private < 1 && ?item_thread_top == 1 in the exclude part of the message filter. This will for example dismiss public toplevel posts (you might not want them in your stream because they are too chatty and you can still see them in the public stream if wanted) while it will still allow public comments and reactions in your stream plus restricted or dm toplevel posts
