include/vlc: Headers clean up.

include/vlc: Headers clean up.

Now "#include <vlc/vlc.h>" defines all the definitions needed to use libvlc_*.

* New layout is the following:
vlc/common.h: Global definitions
vlc/deprecated.h: Deprecated stuff
vlc/libvlc_structures.h: Contains all libvlc_* structures.
vlc/libvlc_events.h: Contains libvlc_event_t structure.
vlc/libvlc.h: Contains all libvlc_* functions
vlc/libvlc_media_list.h: Contains all libvlc_media_list_* functions
vlc/libvlc_vlm.h: Contains all libvlc_vlm_* functions.
vlc/vlc.h: Use this header to use libvlc-control.dylib.