The SubdivisionMethod class provides the names used to set the subdivision
method for a path as class variables.
The subdivision method is used to determine the number of path curve
points N created between two adjacent control points.
Valid subdivision method names are:
SPACING - Divide the distance D between adjacent control points by a
given spacing value S: N = D/S - 1
SUBDIVISION - Set N to a given subdivision number.
TOTAL - Appoximate the total number of path points using the number of
control points Nc and total numner Nt: N = (Nt-1)/(Nc-1) - 1
Get the valid subdivision method names.