Deletes unwanted (practice or error) points from a kinetic isopter.
Only called by function
kFsubj to clean files when
perimeter = 'O'.
This assumes that all Goldmann data have been cleaned and ordered at the point of digitisation.
This function is for internal use and is not meant to be called by the user.
A matrix of coordinates
matrix of coordinates excluding deleted points
Dipesh E Patel & Mario Cortina-Borja