xcp is a (partial) clone of the Unix 'cp' command. It is not intended as a
full replacement, but as a companion utility with some more user-friendly
feedback and some optimisations that make sense under certain tasks (see
below).

Features:
* Displays a progress-bar, both for directory and single file copies. This can
  be disabled with `--no-progress`.
* On Linux it uses `copy_file_range` call to copy files. This is the most
  efficient method of file-copying under Linux; in particular it is
  filesystem-aware, and can massively speed-up copies on network mounts by
  performing the copy operations server-side. However, unlike `copy_file_range`
  sparse files are detected and handled appropriately.
* Non-Linux Unix-like OSs (OS X, *BSD) are supported via fall-back operation
  (although sparse-files are not yet supported in this case).
* Optionally understands `.gitignore` files to limit the copied directories.
* Optimised for 'modern' systems (i.e. multiple cores, copious RAM, and
  solid-state disks, especially ones connected into the main system bus,
  e.g. M.2).