Get the tree pointed to by a commit or stash.
Examples
if (FALSE) { # \dontrun{
## Initialize a temporary repository
path <- tempfile(pattern="git2r-")
dir.create(path)
repo <- init(path)
## Create a first user and commit a file
config(repo, user.name = "Alice", user.email = "alice@example.org")
writeLines("Hello world!", file.path(path, "example.txt"))
add(repo, "example.txt")
commit(repo, "First commit message")
tree(last_commit(repo))
} # }