Increased support for seeding torrents after rename.

Instead of simply leaving an option to keep files when renaming, there are now four options.
Move - Do not keep just move.
Copy - Same as keep before, copy file.
Physical Link - Creates a physical link in the destination folder.
Symbolic Link - Moves the file and creates a link in its original location.

Combining post processing scripts with this will allow using to continue seeding torrents while still having the media files renamed/moved into their TV directories.

I've added linktastic to libs which is used by CouchPotato and nzbToMedia to create symbolic/hard links on both *Nix and Windows systems.

Also I realize that by using nzbToMedia we can create physical links and then just allow sickbeard to move the files. However, not all systems support physical links (unRaid to name one). Additionally, it seems better to me to just include this support in sickbeard itself rather than in the scripts.