GL team fortress sniper fix

Replaces the old X with a big red spiked ball for glQuakeWorld 2.10

Install instructions:
1) Copy cross1.mdl to C:/quake/fortress/progs/cross1.mdl
   That's a subdirectory called progs under the fortress directory.
2) Delete C:/quake/fortress/glquake/cross1.ms2

Quake will recreate cross1.ms2 for you.  

People have gotten it to work so good luck.

   Blank dot?  Delete cross1.ms2  Perhaps there are multiple copies of
   cross1.ms2 somewhere.  It'll be recreated by quake and stored in the
   glquake sub-directory.

   Look for multiple copies of cross1.mdl  The reason why it might remain a
   black X is that the old cross1.mdl was used.  The cross1.mdl installed to
   /fortress/progs should override the others but double check just in case.
   It might be necessary to remove the cross1.mdl in the pak file.  A handy
   utility to do this is "pakexplorer".  Make backups of the pak files
   modified in case something goes wrong!