monoClust 1.2.1

Bugs and Improvements

MonoClus(): default value for distmethod argument is now NULL so that the it can be set to Euclidean (when cir.var is not set) or Gower distance (when cir.var is set).
Fix typos and a trailing space in the warning message of as_MonoClust() function.
Small improvement in how ncores argument is processed in perm.test() and cv.test(). It did not have a problem before but the improvement helps remove errors in Github Actions CI in Windows environment.
\@fig tags in the vignette is removed.
URL to lifecycle badge in README.md is updated.
Start unit test component with the first test is for as_MonoClust() function.

inertia_calc() and medoid() are now exported functions.
is_MonoClust() to check if an object is an inherited class of MonoClust.
Create a S3 function as_MonoClust() so other packages (such as PULS) can reuse print and plot functions. However, no implementation is done in this package.

plot.MonoClust() allows the cols argument to have the length greater than the number of leaves. In that case, function will not throw error and only a subset of it will be used.
MonoClust.object gains alt object as an indicator of whether an alternate route is available.

Remove bipartvar column from frame object of MonoClust object. var column should be sufficient for showing splitting variable names.
alt column in frame object of MonoClust is now a nested tibble containing alternate split details. However, the package does not support specifying an alternate splitting route so users may have to run step-by-step by indicating nclusters = 2 in MonoClust() and then on each branch.
Remove arctic_2019 data set. It was not used anywhere in the examples.

Min version of dependency tibble() is 3.0.0 because tibble::add_row() is used with the new behavior.
Fix some typos and clarify some documentation.

Package is now fully working with all features intended.
Rewrote a lot of internal functions to clean up unnecessary codes.
Added ggplot2 versions of CV plot.
PCP plot for circular data is now named ggpcp and uses ggplot2.
New circular add/subtract operators: %cd+%, %cd-% (in degree), %cr+%, and %cr-% (in radian).
Added wind_sensit_2008 data set.
Added a vignette using R Markdown.
Updated documentation.

MonoClust() removed perm.test and alpha arguments. Users now need to run perm.test() separately to perform permutation test on a MonoClust.
- Removed labels, corders, ran from the output.
- Membership and Dist outputs of MonoClust() are now membership and dist, respectively.
plot.MonoClust() added uniform, branch, minbranch, stats, cols.type, and show.pval.
cv.test() now returns unified output for both LOOCV and k-fold. It includes MSE and SE table and a note with the type of cross-validation.
abbrev argument in plot.MonoClust() and print.MonoClust() now accepts descriptive options "no", "short", "abbreviate".
method argument in perm.test() now uses descriptive options "sw", "rl" and "rn". Users can now decide whether to apply Bonferroni correction with bon.adj argument.
predict.MonoClust() removed na.action. type argument now accepts more meaningful options "centroid" or "medoids".
Added parallel processing capability to perm.test() and cv.test().

Removed the categorical variable feature to make sure it works well for all other cases.