fixed degeneracy issue splitting triangles with one vertex at degenerate location
fixed degeneracy issue splitting triangles with one vertex at degenerate location

YetAnotherMinion/core,yangf4/core,YetAnotherMinion/core,YetAnotherMinion/core,YetAnotherMinion/core,YetAnotherMinion/core,yangf4/core,yangf4/core,yangf4/core,yangf4/core