This patch improves the transition from an interactive window geometry
change (dragging a window element) to the point where the resulting
new layout rules come into effect. During this short time, no resize
request must be issued because such a resize request would be based on
stale rules.
Fixes#3227
This commit replaces the former floating_window_layouter with a new
window_layouter component that supports the subdivision of screen space
into columns and rows, the concept of layers, and the principle ability
to store window layout information across reboots. The latter is
accomplished by reflecting the component's internal state as a 'rules'
report to the outside.
Fixes#3031
