playing state resets the input speed to normal to make sure the
   stream isn't paused or slowed or played faster anymore.
   By doing that, fixes the following bug of the Windows interface:
   when pushing the play button on a paused or slowed stream, nothing
   used to happen.
 * modules/gui/win32/playlist.cpp : when pushing the play button and the
   playlist is empty, displaying the playlist window
 * win32.cpp : rephrasing the module description to "Native Windows
   interface module"