bordered-output: implement recompute-extent-for-changed-child
bordered-output: implement recompute-extent-for-changed-child

we remove replay-output-record :before method (which changed the output record
during repaint protocol going on what was terribly wrong) and remove method for
tree-recompute-extent-aux which is unnecessary.

Fixes #651.

slyrus/mcclim,slyrus/mcclim