bugfixed: The position adjustment in *_*_position() didn't work when show or hide was not NULL.
bugfixed: venn_summary() didn't return subset_elements when show_elements = FALSE.
add vignette and github-pages
bugfixed: The position adjustment in subset_count_position() didn't work when show or hide was not NULL.
bugfixed: highlight() could not handle non-recursive input generated by generate_ellipse_path().
bugfixed: venn_summary() didn't return a value when show_elements = TRUE.
params.R: slightly adjust the first and fourth ellipses coordinates.
This is a resubmission. In this version I have:
Add more details about the package functionality and implemented methods in the Description text.
Remove the testing code containing rm(list = ls()).