I've patched production_log_analyzer so it can read from STDIN.  It does change the command line interface to require
a '-c' for the summary count.  This was necessary as the 'filename' arg is now also optional and there was no way to
distinguish between the count arg and the filename arg.

I would like to have submitted a svn patch, but it appears that the svn repo isn't available (if I'm wrong please let
me know and I'll redo the patch).