TODO:
  - error handling with the errno and strerror function

Perhaps a verification needs to be added, to catch the situations when
the user specifies a non-existing directory? (and either create it or
abort with "no such directory", instead of claiming there's no free
space)


THOUGHT-ABOUT FEATURES
  - being able to specify
     - which title
     - which chapter
     - which angle 
     - which language(s)
     - which subtitle(s)
     to copy
  - print the total playing time of that title
 
