Author: Nicolae Cindea
ellipseMatrix(y0, x0, a, b, teta, Image, color)
Set the elements of the matrix Image which are in the interior of the
ellipse E with the value color. The ellipse E has center (y0, x0), the
major axe = a, the minor axe = b, and teta is the angle macked by the
major axe with the orizontal axe.
This is a great function for creating ellipses in an image matrix. Since circles are simplified ellipses it can be used to make those too. V1.1 puts a single pixel nerd on the NSEW ends for the circle (semimajor = semiminor) and for some ellipses.