Rename Copyrights to COPYRIGHTS for consistency with other filenames

COPYRIGHTS

@@ -0,0 +1,26 @@
+
+In general gPXE files are licensed under the GPL.  GPLed files are in
+general either from Linux or have been explicitly put under GPL by the
+authors.  The license for a file is usually documented at the top of
+the file.  
+
+A few files are inherited from FreeBSD netboot and therefore can be
+used under BSD or GPL.  Documented in this file are some of the
+non-GPL'ed files.  If the internal documentation for a file disagrees
+with what is documented in this file, the internal documentation for
+the file shall be override this file.
+
+File					Copyright status
+
+src/core/misc.c				BSD
+src/drivers/net/3c509.c			BSD
+src/drivers/net/3c509.h			BSD
+src/drivers/net/3c595.c			BSD
+src/drivers/net/3c595.h			BSD
+src/drivers/net/3c90x.c			Open Source
+src/drivers/net/epic100.c		None
+src/drivers/net/epic100.h		None
+src/drivers/net/ns8390.c		BSD
+src/drivers/net/ns8390.h		BSD
+src/arch/i386/include/bits/string.h	None
+