In cases like multiple hi-res monitors connected through a USB dock, the
preferred mode can fail to work. Such an output was then ignored by river,
which made it impossible to even set another mode manually.
Sway has been reported to solve this issue, so let's employ their solution
and fall back to another mode if possible.
Until now, Seat.setFocusRaw sent all pressed keys to the client,
including ones that should be eaten. (Try e.g. changing focus to a
nested wlroots compositor with a terminal open to easily see it.)
However, only filtering out the eaten keys is not enough; they were
eaten only once all mappings had been executed. Therefore, the original
function had to be split into one looking up mappings and another
executing them.
Until now, only the event (press/release) for which a mapping was
present got eaten, and the other was passed to the client. From this
commit, a press mapping eats both events and a release mapping eats
nothing (and a press+release combo eats both).
This fixes behavior of some clients that do not make a difference
between press and release (e.g. Firefox with a fullscreen video
exiting fullscreen even on an Esc release event).
I have encountered a crash (failing assert) if a view specified a fixed
size less than this minimum, and according to ifreund this behavior was
planned to be removed, anyway.
