Atomic file-writes.
The basic idea is to write to temporary files, and move them when done writing.
This avoids the problem of two programs writing to the same file. For
AllowOverwrite, rename is used. For DisallowOverwrite, link + unlink is used
instead to raise errors when the target path already exists.
This package contains library source intended for building other packages
which use "default" feature of "atomicwrites" crate.
