Helper function for the plot functions to add variable labels to the predictor and response variable axes
make.df.for.varlabels(BV, margins, names, P, R)
df with information for the placement of the variable labels
Concatention of matrices B (P x S) and V (R x S) or only V (R x S) from lpca
a vector of length four indicating the margins of the plot
a vector with variable names
an integer indicating the number of predictor variables
an integer indicating the number of response variables