*) Changed configure.in to check for all header files the macosx plugin needs

*) Changed configure.in to check for all header files the macosx plugin needs
*) There is now an option --disable-macosx, instead of --enable-macosx.
   --disable-macosx is default for all plattforms except MACOSX
*) The mouse cursor is hidden when playing in fullscreen mode
*) The screensaver is deactivated when playing in fullscreen mode
   (Thanks to Julian Mayer <julianmayer>@mac.com)
*) Stop, Prev and Next buttons work now.