New algorithm for quad meshing (delquad)

Common/CommandLine.cpp

Common/GmshDefines.h

Common/Options.cpp

Fltk/optionWindow.cpp

Geo/MElementOctree.cpp

Mesh/BackgroundMesh.cpp

Mesh/Field.cpp

Mesh/HighOrder.cpp

Mesh/meshGFace.cpp

Mesh/meshGFaceBDS.cpp

Mesh/meshGFaceDelaunayInsertion.cpp

Mesh/meshGFaceDelaunayInsertion.h

benchmarks/2d/Square-01.geo

benchmarks/2d/conge.geo

benchmarks/2d/recombine.geo

benchmarks/2d/slot.geo

benchmarks/2d/wing-splines.geo