1x1 sprites will not stamp after a "say" block is executed #528
Description
Expected Behavior
The "stamp" block should work consistently
Actual Behavior
If a block which causes a speech bubble to appear ("say", "think", "ask") is executed before the "stamp" block, sprites whose texture size is 1x1 will not stamp.
Sprites whose texture size is 1 in one dimension but not the other will produce a 1-pixel line.
This probably has something to do with convex hull calculations.
EDIT: it looks like the "tight" bounds from convex hull calculations are shrunk by one costume-space pixel in all cases.