Benefits are that we don't open a fake container and don't call many
complicated functions that can lead to redraws (x_push_changes calls) as
discussed in #2954.
Fixes#2810:
Windows exchange floating mode & window rects.
Swap will still not work with CT_FLOATING_CONs but this doesn't make
much sense.
Fixes#3280:
The behaviour is not very user friendly but swap behaves exactly as it
should. The rest is a tree_flatten issue. Attached pictures in #2954.
When we don't modify the focus we aren't risking giving focus to a
container behind the current fullscreen one.
_con_move_to_con can with ignore_focus is called through the swap
command or through con_move_to_workspace for floating containers. This
change shouldn't break the expectations of the callers there.
Fixes issue #3259.
Michael Stapelberg