This interface must be implemented by any snip class who’s
objects will be stretchable when inserted into an
aligned-pasteboard<%>.
(send a-stretchable-snip get-aligned-min-height) → real?
The minimum height that the snip can be resized to
(send a-stretchable-snip get-aligned-min-width) → real?
The minimum width that the snip can be resized to.
(send a-stretchable-snip stretchable-height) → boolean?
Whether or not the snip can be stretched in the Y dimension
(send a-stretchable-snip stretchable-width) → boolean?
Whether or not the snip can be stretched in the X dimension