Change notes

To-dos

function (that calls predict_delta_comps()) that does the minutes in the day specifically by default (also deltas in minutes rather than proportions in output)
additional commenting
additional unit tests
remove compositions package dependency

Improved 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?)

fixed error in append_ilr_coords() that would create errors when a single row data.frame was passed (failing unit tests and examples). Seemed to be a new way the compositions package handled data potentially, or the move to R 4.0

the main function get_plus_minus_changes() has been more sensibly renamed to predict_delta_comps()
refactor and modularisation of predict_delta_comps()
the two types of reallocation (prop-realloc and one-v-one) are working correctly, unit tested
includes more checks to throw errors for obvious malfunctions
the mean composition now correctly uses the geometric mean (on the simplex) and not the naive arithmetic mean of the compositions
added plotting function plot_delta_comp() (see '5. Output and plotting results' below)
predict_delta_comps() now removes rows with NA values in input datasets (and warns the user)
the mean composition and the resulting predicted outcome with confidence interval is now produced by predict_delta_comps() (see '5.1 Prediction for the mean composition' below)
predict_delta_comps() now checks for compositional components of 0 [or non-sensical negative values] (geometric mean incompatable)
completed general testing and unit tests