Add and improve the package documentation information in the DESCRIPTION file.
Add dontrun tags to the examples that require an internet connection to run per http://cran.r-project.org/doc/manuals/r-release/R-exts.html#Documenting-functions
Improve the example for the function `download()`. The directory `data` has special significance in R packages so it is a bad idea to download data to a direcoty of that name.
Add url to the overview of available datasets to the help file of the `datasets()` function.
Change "data files" to "datasets" in DESCRIPTION file.
Merge pull request #24 from dmcglinn/pkg_data

Update the package DESCRIPTION file
Merge pull request #25 from dmcglinn/better_docs

Improve the documentation of the functions