Subdivide faces only

Being able to use the subdivision modifier as a modifier before cloth simulation is important for having enough faces to simulate while retaining the ability to easily edit the low-poly mesh.

Unfortunately, this doesn't play nice with stitching, because stitching edges also get subdivided, and the resulting edge loops produce significantly degraded results compared to single edges.

At least for "simple" subdivision (which is what is typically used for cloth simulation, anyway), this can be trivially fixed by simply not dividing edges not associated with faces.