Patch for helping crossfader

Hello!

Problem: From within an Output plugin, it is currently impossible to 
reliably detect wether the plugin is closed for End-Of-Playback/STOP or 
just for a songchange. The crossfade-plugin needs to know this in order to 
decide wether to keep the device opened or not.

Attached is a patch against XMMS-1.2.7. It modifies XMMS so that it sets a 
flag (input_stopped_for_restart()) before each input_close(). This flag is 
TRUE when another playlist entry is to be played immediteally after the 
input_close(). It is FALSE otherwise (on STOP or at the end of the playlist).

The patch should be transparent to any other xmms code or plugins, although 
this needs more testing/review.

Suggestions are welcome on how to do this better. Also, the function names 
introduced can be renamed to match the existing naming style. If the patch 
is accepted, I will modify XMMS-crossfade to make use of the flag. This 
should fix a range of timeout-related problems with crossfading. The patch 
might also be usefull for other plugins, although I currently can't think 
of any ;)

cya & Merry Christmas!

   Peter