* Changed the default execution shell to sh instead of bash
* Added --from and --to command-line parameters for date selection
* Added vim folds
* Added some more comments
* Re-worked the list_indices function. No more find(1) with -mtime, we
  use ls(1) and custom-made date detection now. The old solution was
  wrong on several levels, the new one should work.
* Added date functions
* Re-worked the parse_args() function. The "$@" vs $@ is a bitch with
  arguments that contain spaces! Had to check the exaples in
  /usr/share/doc/util-linux/examples/getopt-parse.bash to figure it out!
* Re-worked the check_CONF_* stuff. It used to spawn a subshell before,
  and that means subtle side-effects. Namely, you could not set a global
  variable in these functions. Now it doesn't spawn a subshell and
  everything works as expected.
* Probably some more bugfixes that I can't remember now...
* Added vim folds
* Some more comments
* Re-worked the list_indices function. No more find(1) with -mtime, we
  use ls(1) and custom-made date detection now. The old solution was
  wrong on several levels, the new one should work.
* Re-worked the check_CONF_* stuff. It used to spawn a subshell before,
  and that means subtle side-effects. Namely, you could not set a global
  variable in these functions. Now it doesn't spawn a subshell and
  everything works as expected.