Initialization function for the "Effloglog" class
Effloglog(Eff, Effdose, nu, data, c = 0)the pseudo efficacy responses
the corresponding dose levels for the pseudo efficacy responses
the precision (inverse of the variance) of the efficacy responses
the constant value added to the dose level when the dose level value is less than or equal to 1 and a special form of the linear log-log has to applied (Yeung et al. (2015).).