helper script to update libraw and rawspeed from their repositories

Hi, this is a bash script to update rawspeed and libraw files  from their upstream repositories.
generated files are local, to be stashed away or removed.  no repo changes.

see also 
From: Wolfgang Goetz <Wolfgang.ztoeG@web.de>
To: darktable-devel@lists.sourceforge.net <darktable-devel@lists.sourceforge.net>
Subject: [darktable-devel] Updating LibRaw and rawspeed
Date: Tue, 6 Aug 2013 23:04:57 +0200