Some methods have been moved into another class (like the simple linear interpolation between two points that is now in ResamplingAlgorithms), some renammed (like the new weightedMean that replaces the ill-nammed "linearInterpolate"). The regression model based on two segments is now part of libinterpol1D and has been renammed. More regression models have been implemented. 

The "initFit" method of Fit1D has been renammed in "fit" and the setGuess method now turns fit_ready to true, so that a user can force his provided parameters to be used by a given model (do a setGuess() with the parameters, then call f(x) without calling "fit", so no internal fit of the parameters would be performed).