stream: remove useless author/comment fields

These were printed only with -v. Most streams had them set to useless
or redundant values, so it's just badly maintained bloat.

Since we remove the "author" field too, and since this may have
copyright implications, we add the contents of the author fields to
the file headers, except if the name is already part of the file header.

stream/stream_memory.c

@@ -73,10 +73,7 @@ static int open_f(stream_t *stream, int mode, void* opts)
 }
 
 const stream_info_t stream_info_memory = {
-    "Memory",
     "memory",
-    "",
-    "",
     open_f,
     { "memory", NULL },
 };