Add a input_Read function that reads a stream in blocking or non-blocking mode and cleans-up (Closes:#244)

Still needs to be exported, but needs some thinking for pause/stop handling

Also removed a long unused member from the clock struct.

   coordinates and/or invalid size

   when the extraction failed

 depends on the position of the slider. The "Slider" elements now
 have optional attributes "background", which the Id of a bitmap,
 and "nbimages" which is the number of images in the bitmap (it
 is similar to the radialslider). At the moment there is a hack
 to support winamp slider bars: the different images must be
 separated by 3 rows of unused pixels (well, maybe they are
 useful; if someone knows how... ;)
* theme_loader.cpp: convert the file names from zip archives to 
  lower case, to avoid mixed case issues in some winamp skins

bootstrap: test for the presence of contrib/share/aclocal before including it because m4 react badly to missing directory

 * skins2/src/theme_loader.cpp: Fixed another directory delimiter issue. The winamp skins load perfectly on windows now...

* winamp2.xml: more controls

* theme_loader.cpp: correct handling of subdirectories in winamp
  skins

 lot of things to do but it works !
* theme_loader.cpp: when a theme contains no XML file, assume
 we are trying to load a winamp skin, and use winamp2.xml
* vlcproc.cpp: repaired text variables ($N was broken)

  several bitmaps in a skin from regions of the same image file.
  Usage is:
  <Bitmap id="body" file="main.bmp" alphacolor="#FF0000">
    <SubBitmap id="sub1" x="0" y="10" width="100" height="100" />
    <SubBitmap id="sub2" x="100" y="10" width="100" height="100" />
  </Bitmap>

  Borrowed code from Gilles Vollant for the unzip part
  (I guess this code should be put elsewhere in vlc, but it was
  the easy way for me at the moment;) I hope it compiles fine
  everywhere, I've tested only on linux.
  Now, everything's ready for winamp skins ;)

 can be loaded

 taken into account, which caused getting RGBA pictures instead of ARGB,
 or GBR instead of RGB). 8bpp is obviously broken too, I have not tested it.
 --> now BMP images (and other formats) can be used in skins, not only PNG!
  (of course the goal is to add a winamp skins loader ;-)

 "equalizer.enable()" and "equalizer.disable()" to enable
  or disable the equalizer audio filter.
  + small fixes

Bug report credited to Matthew Hodgson