NOTE: libvlc API changes

* renamed VLC_Stop to VLC_CleanUp since this name is closer to what it actually does.
* added a new VLC_Stop that just does playlist_Stop analogous to VLC_Play and VLC_Pause.
* reordered the functions in libvlc. everything was mixed up.
* added doxygen info to all the functions
* fixed several functions to use the correct underlying API calls
* corrected the copyright info


This is in preparation of the new libvlc calls for mozilla plugin
temp. moved the playlist_command_t typedef to vlc_common.h awaiting implementation of playlist_Control()