Log qualities.
Moved labels and label functions to ISMesh.
Deleted unused multi face retriangulation functions from ISMesh.
Added a flip 4-4 function to ISMesh (also handles 2-2 flips).
Added DEBUG assertions to 3-2 flip and 2-3 flip functions.
Print the effectiveness of edge flips.
Moved check from flip() to is_flippable().
Added a new flip function (border_flip) which is not working yet.