This function will take the specified data frame and will perform linear
discrimination analysis with leave-one-out crossvalidation and equal priors
for each individual (e.g., all priors will be set to 1/10 in case that the
dataset contains 10 individuals). Variables are not modified in any way;
scaling, centering, transformation of variables, or principal component
analysis, etc., if required, need to be done on dataset before calling this
function. Reference: e.g. Hafner, G. W., Hamilton, C. L.,
Steiner, W. W., Thompson, T. J., & Winn, H. E. (1979). Signature information
in the song of the humpback whale. Journal of the Acoustical Society of
America, 66, 1-6. doi:10.1121/1.383072