convergence threshold. When
abs(new.deviance-old.deviance)/(old.deviance + epsilon) < epsilon
the algorithm is assumed to have converged.
maxit:
maximum number of iterations
trace:
should iteration details be printed while glm() is fitting the model.
VALUE:
a list is returned, consisting of the three parameters, conveniently
packaged to supply the control argument to glm(). The values for
glm.control() can be supplied directly in a call to glm(). These
values are then filtered through glm.control() inside glm().