Copies files to a target directory. Takes the following arguments:
read
Hash whose keys are the names of the files to be copied, typically
returned by maniread.
target
Target directory into which files are to be copied.
how
Can be used to specify a different method of "copying." Values are:
Copy the files.
Create hard links.
Link the files, but copy any symbolic link to make a tree
with no symbolic links. (The default.)