Expand 2nd wall regions more when merging with outer wall to ensure polygons meet.
Expand 2nd wall regions more when merging with outer wall to ensure polygons meet.

When combining fragments of the outer wall and 2nd walls, if the 2nd wall fragments are
small and have sharp corners (e.g. small triangles or fillets) then unless the 2nd wall
fragments are expanded by a whole line width, they may not meet up with the outer wall
sections and so the combing area will not become a single polygon.

Ultimaker/CuraEngine,Ultimaker/CuraEngine