* libvlc sources and plugins now define __LIBVLC__ and headers exported to
plugins (ie, include/vlc_*.h) check for this
* libvlc sources use the value of the "libvlc" component in vlc-config instead
of vlc
* Apply flags directly to "libvlc" in configure.ac - might temporarily break win32 :)
* include/vlc_xml.h, src/misc/xml.c: core wrapper for XML modules.
* modules/misc/xml/xtag.c: trivial XML parser module.
* modules/misc/xml/libxml.c: XML parser module using libxml2.
* modules/gui/skins2/parser/*: removed dependancy on libxml2 and use an XML module.