Lists, or deletes, the pre-built wind rose files that download_wind_rose() has saved to the
cache. The cache is in the user cache directory given by tools::R_user_dir("windscape", "cache"); set options(windscape.cache_dir = ...) to use a different location.
Value
A data frame of cached files, with columns file, release, bytes, and path
(invisibly, listing the deleted files, if clear = TRUE).
