Decker

fix crash/incorrect behavior for %J formatting when using an invalid interface type as input, per #93.

overhaul eval[] to supply information about where in the supplied strings errors were encountered, if any.

weekly challenge problems 283.1, 283.2

introduced Edit -> Add Outline for selected images, saving time on a tedious operation that is often useful when creating semi-transparent canvases.

correct inaccuracy/mismatches between dr.omask and dr.mask when moving regions with the lasso tool, and internally add some guards/reworks to avoid the unsafe assumption that dr.omask and dr.mask have the same size.