Since layout panes use the upper-left corner of the region of the child in order to determine the sheet transformation of the same child, the region of the child must exist with a valid upper-left corner.  The dimensions can be arbitrary.  Added code to allocate default rectangular region of sheets with upper-left corner at (0,0).
Since layout panes use the upper-left corner of the region of the child
in order to determine the sheet transformation of the same child, the
region of the child must exist with a valid upper-left corner.  The
dimensions can be arbitrary.  Added code to allocate default rectangular
region of sheets with upper-left corner at (0,0).

Fixed definition of sheet-disown-child.

Fixed definition of sheet-delta-transformation.

note-sheet-disowned no longer calls note-sheet-degrafted.

sheet-disown-child now calls note-sheet-degrafted when former parent of
disowned child is grafted.

Removed multiple definition of condition sheet-already-has-parent.

Replaced occurences of `ignorable' to occurences of `ignore'.

onixie/mcclim,slyrus/mcclim,swflint/McCLIM,onixie/mcclim,onixie/mcclim,swflint/McCLIM,antifuchs/mcclim,antifuchs/mcclim,slyrus/mcclim,swflint/McCLIM