Added cdev, initial implementation

This has private external dependencies, so you can't use this version.
Polished version, with no external dependencies

Now, you can use it, too.
Cooler name: let the fun & dancing begin!
Very improved version: 1.0

New features
 - version info
 - can alter link type: symbolic or hard link, or copy
 - choose whether to overwrite existing files

Incompatibilities:
 - short form -c (of --dest-cdev) was changed to -d to allow for --copy
Very nice README

(It explains how everything should work; and how it doesn't)