flat/tree view seems to be controlled by playlist-tree option these days

- remove some messages logging dead code
- don't store the ncurses WINDOW, use global stdscr instead
- add some fancy unicode characters to the help
- factorize list navigation key handling
    all boxes now use the same code than PLAYLIST/BROWSE
    this means there is now a selector in every box
- break Redraw() in several functions
- remove fancy characters from Status box drawing code
    use the same layout than meta-info / info boxes
- fix a display bug in objects box
- simplify some functions and remove unneeded arguments
- avoid a strdup() in ReadDir() loop

        Known regressions:
- when switching back to PLAYLIST box, the selector will be set to the
  playing item only after the 2nd refresh (i.e. maximum 1 second later)

And improve consistency

Yes, this still works fine as long as it's used in that one place in
the VLM.

Only one track per file implemented yet

This uses some unspecified C++ statically linked version of GME.
That does not correspond to libgme, and seems unused.

Our PO files are all encoded in UTF-8, and VLC always binds its text
domain as UTF-8. There is no need to convert localized strings. So
libintl does not need to use iconv.

This should help a lot the future work.

We can't use the VLM object because the instances and their input
resources are cleaned up in the VLM destructor

This reverts commit d38706da.

Changed back, as changed loop didn't do same as original did

Also assume p_item->i_es is set correctly

- use switch/case instead of if/else if/else if
- factor out HandleEditBoxKey() and HandleCommonKey()
- return bool instead of int

Use one line per switch label when it improves readability
Also explicit the sign of position increment even when positive so +x and -x are aligned

And cleanup includes of StandardPanel

Remove friendship
Factorisation of CoverArt
Reduction of class footprints
virtual and protected correctness
Forward declaration when possible