* ./include/vlc/vlc.h: changed the naming conventions for libvlc. Now
    exported functions start with VLC_ instead of vlc_ to avoid conflicts.
  * ./include/vlc/vlc.h: removed the vlc_object_t, vlc_list_t, vlc_error_t
    and vlc_t types; they are now internal types only.
  * ./include/vlc/vlc.h: merged the reentrant and non-reentrant libvlc
    calls. In non-reentrant mode, we just use 0 as the first argument. In
    reentrant mode, we use an object's ID. (see below)

Internal changes:
  * ./src/libvlc.c, ./src/misc/objects.c: instead of manipulating vlc_object_t
    pointers, we manipulate their i_object_id. When needed, an object is
    retrieved using vlc_object_get (I hope the lookup isn't too expensive,
    that's why I designed the pp_objects layout to allow log2(n) seeks).
  * ./src/misc/objects.c: activated the per-object variable storage. Unused
    yet, unless you want to try "getfoo" and "setfoo blablah" in vlc -I rc.
  * ./include/vlc_objects.h: moved the vlc_object_t and vlc_list_t definitions
    here.

Misc:
  * ./src/vlc.c, ./mozilla/vlcshell.cpp: removed inclusion of config.h in
    code portions not part of libvlc; it was just required for the
    COPYRIGHT_MESSAGE string which is now available from VLC_Version().