Add the ability to show/rm using a movie symlink as argument

[Antoine Millet]

It should be nice to get the ability to use show/rm/find-duplicates commands using a symlink to the movies as argument.

Example:

$ kolekto rm ./Testmovie.mkv
                              ^-- Symlink to .kolekto/movies/{hash}

Instead of:

$ kolekto rm {hash}