tystan/deltacomp: deltacomp version 0.2.2

Version 0.2.2 improves the printed output:

• The output to console is now better spaced with dividers (---) for easier reading
• The ilrs (ilr1, ilr2, ...) are defined in terms of the input compositional variables in predict_delta_comps() output (printed to console)
• predict_delta_comps() now prints to the console a statistical test for the ilrs being collectively significant in the model (i.e., do they improve the model statistically?)