MIRRORED-SHEET-MIXIN     new slot: MIRROR-TRANSFORMATION, we'll need that soon.
MIRRORED-SHEET-MIXIN
    new slot: MIRROR-TRANSFORMATION, we'll need that soon.

NOTE-SHEET-GRAFTED :before mirrored-sheet-mixin
    Added error message, in case the sheet has no port.

quek/mcclim,informatimago/mcclim,quek/mcclim,informatimago/mcclim