Cleaned up bugs with stream implementation

Principle was that we may have read all the content from the
underlying pipe (s.t. it set the EoF flag) but we haven't actually
iterated the content.

stream.c

@@ -142,7 +142,9 @@ char stream_next(stream_t *stream)
 
 char stream_peek(stream_t *stream)
 {
-  if (stream_eos(stream))
+  // If we've reached end of stream, and end of content, there's really nothing
+  // to check here.
+  if (stream_eoc(stream) && stream_eos(stream))
     return '\0';
 
   switch (stream->type)