rename()
  Interscanner to rewrite virus name returned by an scanner.
  
  Usage: rename(newname, scanners)
     or: rename(newname, scanners).multiplier(MP)
  
  Where: newname is a string, which defines new virus name.
         These string will be replaced:
           %(VIRNAME)s          old name
           %(LEVEL)s            detected level as float
           %(STARS)s            detected level as stars
         MP is an multiplier for LEVEL and STARS. Returned level
           is multiplied by this constant.
  
  Renaming is skipped, if level<1.0.