main_interface: update the systray tooltip

               - Repair the quit-VLC-but-let-the-menu W32 bug,
               - add an option to start VLC minimized.

Mostly patch by  Sergey Volk

Comment out a few non-thread-safe functions from embedded vout
handling. Fixes a crash when playlist item changes. refs #955

  - Return correct item ids
  - Structures for navigating the playlist
  - Consistent locking
* Add a b_locked parameter to the remaining playlist API calls

Control & Playback buttons have the same size

* Headers in include must contain the structures and prototypes needed
  by the plugins and should be named vlc_*.
* Headers in include/vlc must contain the structures and prototypes
  needed by external libvlc clients

* Moved and renamed some things in headers. 
   - Removed vlc_cpu.h, vlc_error.h (merged in vlc_common)
   - Removed snapshot.h (merged in vlc_vout.h)
   - Removed vlc_spu.h (merged in vlc_osd.h)
   - Removed intf_eject.h and vlc_interaction.h (merged in vlc_interface)
   - Moved all internal headers to src
   - Merged vlc_video.h and video_output.h and move private things to src
   - Removed vlc/intf.h, vlc/aout.h, vlc/vout.h, vlc/decoder.h and vlc/input.h
     (meta headers for use in modules, and often implying too large 
     dependencies)
* Removed some useless dependencies
* Unexported a bunch of functions and structures used only in src/
  (--> Still some work here)
* Finally made input_thread_t and input_source_t (mostly) private. 
  Added input_GetItem to fetch the input_item of an input_thread
* Cleaned up deprecated entries in vlc_symbols.h and bumped up symbol 
  prefix

This commit has a 99% probability of breaking the build, 0.1% of killing
your cat and 0% of getting you hot chicks.

* Remove some unneeded wrappers and locking

 * Remove the random special case
 * Use the array of currently playing items for all cases
 * Convert array items to array API
 * Replace standard searches in sorted arrays by bsearches
 * Size is not yet fixed (next round).

Array
 * Add reset/value and bsearch functions
 * Add foreach helper

  p_libvlc->b_die
  Not implemented for OS X as I am not sure, please check if it is feasible.
* Don't run the dummy interface

* Fixes to dialog singletons
* Forgotten files (definitions of aout_Visual*, unimplemented at the moment)

Make some sttings persistent

Put the add button in the playlist standard panel
Remove duplicated code for playlist widgets

Add button in playlist widget