R package regtools: Regression Tools. Tools for linear, nonlinear and nonparametric regression and classification. Parametric fit assessment using nonparametric methods. One vs. All and All vs. All multiclass classification. Nonparametric regression for general dimension, locally-linear option. Nonlinear regression with Eickert-White method for dealing with heteroscedasticity, k-NN for general dimension and general descriptive functions.