Minor code tweaking.
Minor code tweaking.

* Commented out many debug prints.
* Change edge degeneracy threshold to 1e-15, used to be 1e-12.

There is still one test the current version failed: when all adjacent faces of
an degenerated edge are coplanar in float but not in exact.  Need to think about
what to do in this case.

JianpingCAI/libigl,JianpingCAI/libigl,aaronzou/Shape-Deformation,JianpingCAI/libigl,aaronzou/Shape-Deformation,JianpingCAI/libigl,JianpingCAI/libigl,aaronzou/Shape-Deformation,aaronzou/Shape-Deformation,aaronzou/Shape-Deformation,JianpingCAI/libigl