The following are the edge data channel index values for use
with the edge data methods of class
MNMesh and class EPoly.
EDATA_KNOT: The edge knot data. This is index
0.EDATA_CREASE: The crease data. This is index
1.1 through
MAX_EDGEDATA-1: Developer defined data. Note:
#define MAX_EDGEDATA 10