Correct a bug (the trick have to be tried if the resulting point is not better than the original one)

of extrema

of the 1-star is the same as the others)

be run)

a cut)

Conflicts:
	src/topology/MeshPLCut.cpp
	src/topology/MeshPLCut.h

mesh. Correct a bug on the corresponding function

the existing vertices before cutting the mesh

to be not too small)